diff --git a/src/utilities/RegistryFilter.ts b/src/utilities/RegistryFilter.ts
new file mode 100644
index 0000000..390c78e
--- /dev/null
+++ b/src/utilities/RegistryFilter.ts
@@ -0,0 +1,486 @@
+import { Registry } from '../Registry';
+import { DeviceRegistryEntry } from '../types/homeassistant/data/device_registry';
+import { EntityCategory, EntityRegistryEntry } from '../types/homeassistant/data/entity_registry';
+import { RegistryEntry, StrategyConfig } from '../types/strategy/strategy-generics';
+import { logMessage, lvlDebug } from './debug';
+
+/**
+ * A class for filtering and sorting arrays of Home Assistant's registry entries.
+ *
+ * Supports chaining for building complex filter queries.
+ *
+ * @template T The specific type of RegistryEntry being filtered.
+ */
+class RegistryFilter<T extends RegistryEntry, K extends keyof T = keyof T> {
+  private readonly entries: T[];
+  private filters: (((entry: T) => boolean) | ((entry: T, index: number) => boolean))[] = [];
+  private readonly entryIdentifier: ('entity_id' | 'floor_id' | 'id') & K;
+  private invertNext: boolean = false;
+
+  /**
+   * Creates a RegistryFilter.
+   *
+   * @param {T[]} entries Registry entries to filter.
+   */
+  constructor(entries: T[]) {
+    this.entries = entries;
+    this.entryIdentifier = (
+      entries.length == 0 || 'entity_id' in entries[0] ? 'entity_id' : 'floor_id' in entries[0] ? 'floor_id' : 'id'
+    ) as ('entity_id' | 'floor_id' | 'id') & K;
+  }
+
+  /**
+   * Inverts the outcome of the next filter method in the chain.
+   *
+   * @remarks
+   * Double chaining like `.not().not().whereX()` cancels out the inversion for whereX().
+   */
+  not(): this {
+    this.invertNext = !this.invertNext;
+
+    return this;
+  }
+
+  /**
+   * Resets the internal filter chain, allowing the instance to be reused for new filtering operations on the same set
+   * of entries.
+   */
+  resetFilters(): this {
+    this.filters = [];
+    this.invertNext = false;
+
+    return this;
+  }
+
+  /**
+   * Adds a custom filter predicate to the filter chain.
+   *
+   * @param {(entry: T) => boolean} predicate A function that takes a registry entry and returns true if it should be
+   *                                          included.
+   */
+  where(predicate: (entry: T) => boolean): this {
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters entries **strictly** by their `area_id`.
+   *
+   * - Entries with a matching `area_id` are kept.
+   * - If `areaId` is `undefined` (or omitted), entries without an `area_id` property are kept.
+   * - If `expandToDevice` is `true` and the entry's `area_id` is `undisclosed`, the device's `area_id` is used.
+   *
+   * @param {string | undefined} areaId - The area id to match.
+   * @param {boolean} [expandToDevice=true] - Whether to use the device's `area_id` if the entry has none.
+   */
+  whereAreaId(areaId?: string, expandToDevice: boolean = true): this {
+    const predicate = (entry: T) => {
+      let deviceAreaId: string | null | undefined = undefined;
+      const entryObject = entry as EntityRegistryEntry;
+
+      if (expandToDevice && entryObject.device_id) {
+        deviceAreaId = Registry.devices.find((device) => device.id === entryObject.device_id)?.area_id;
+      }
+
+      if (areaId === 'undisclosed' || areaId === undefined) {
+        return entry.area_id === areaId && (!expandToDevice || deviceAreaId === areaId);
+      }
+
+      return entry.area_id === areaId || (expandToDevice && deviceAreaId === areaId);
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+    return this;
+  }
+
+  /**
+   * Filters entries by whether their name contains a specific subString.
+   *
+   * It checks different name properties based on the entry type (name, original_name, name_by_user).
+   *
+   * @param {string} subString The subString to search for in the entry's name.
+   */
+  whereNameContains(subString: string): this {
+    const lowered = subString.toLowerCase();
+    const predicate = (entry: T) => {
+      const entryObj = entry as { name?: string; original_name?: string; name_by_user?: string };
+
+      return [entryObj.name, entryObj.original_name, entryObj.name_by_user]
+        .filter((field): field is string => typeof field === 'string')
+        .some((field) => field.toLowerCase().includes(lowered));
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters entities by their domain (e.g., "light", "sensor").
+   *
+   * @param {string} domain The domain to filter by.
+   *                        Entries whose entity_id starts with the domain are kept.
+   */
+  whereDomain(domain: string): this {
+    const prefix = domain + '.';
+    const predicate = (entry: T) => 'entity_id' in entry && entry.entity_id.startsWith(prefix);
+
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters entries by their floor id.
+   *
+   * - Entries with a **strictly** matching `floor_id` are kept.
+   * - If `floorId` is undefined (or omitted), entries without a `floor_id` property are kept.
+   *
+   * @param {string | null | undefined} [floorId] The floor id to strictly match.
+   */
+  whereFloorId(floorId?: string | null): this {
+    const predicate = (entry: T) => {
+      const hasFloorId = 'floor_id' in entry;
+
+      return floorId === undefined ? !hasFloorId : hasFloorId && entry.floor_id === floorId;
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters entries by their device id.
+   *
+   * - Entries with a **strictly** matching `id` or `device_id` are kept.
+   * - If `deviceId` is undefined, only entries without both `id` and `device_id` are kept.
+   *
+   * @param {string | null | undefined} [deviceId] The device id to strictly match.
+   */
+  whereDeviceId(deviceId?: string | null): this {
+    const predicate = (entry: T) => {
+      const hasId = 'id' in entry;
+      const hasDeviceId = 'device_id' in entry;
+
+      if (deviceId === undefined) {
+        return !hasId && !hasDeviceId;
+      }
+
+      return (hasId && entry.id === deviceId) || (hasDeviceId && entry.device_id === deviceId);
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+    return this;
+  }
+
+  /**
+   * Filters entities by their id.
+   *
+   * - Entities with a matching `entity_id` are kept.
+   * - If `entityId` is undefined, only entries without an `entity_id` property are kept.
+   *
+   * @param {string | null | undefined} [entityId] The entity id to match.
+   */
+  whereEntityId(entityId?: string | null): this {
+    const predicate = (entry: T) =>
+      entityId === undefined ? !('entity_id' in entry) : 'entity_id' in entry && entry.entity_id === entityId;
+
+    this.filters.push(this.checkInversion(predicate));
+    return this;
+  }
+
+  /**
+   * Filters entries **strictly** by their `disabled_by` status.
+   *
+   * @param {EntityRegistryEntry['disabled_by'] | DeviceRegistryEntry['disabled_by'] | undefined} [disabledBy]
+   *   The reason the entry was disabled (e.g., "user", "integration", etc.).
+   *   Entries with a matching `disabled_by` value are kept.
+   *   If `disabledBy` is undefined, only entries without a `disabled_by` property are kept.
+   */
+  whereDisabledBy(disabledBy?: EntityRegistryEntry['disabled_by'] | DeviceRegistryEntry['disabled_by']): this {
+    const predicate = (entry: T) => {
+      const hasDisabledBy = 'disabled_by' in entry;
+
+      return disabledBy === undefined ? !hasDisabledBy : hasDisabledBy && entry.disabled_by === disabledBy;
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters entities by their `hidden_by` status.
+   *
+   * @param {EntityRegistryEntry['hidden_by'] | undefined} [hiddenBy]
+   *   The reason the entity was hidden (e.g., "user", "integration", etc.).
+   *   Entries with a matching `hidden_by` value are included.
+   *   If undefined, only entries without a `hidden_by` property are included.
+   */
+  whereHiddenBy(hiddenBy?: EntityRegistryEntry['hidden_by']): this {
+    const predicate = (entry: T) => {
+      const hasHiddenBy = 'hidden_by' in entry;
+
+      return hiddenBy === undefined ? !hasHiddenBy : hasHiddenBy && entry.hidden_by === hiddenBy;
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+
+    return this;
+  }
+
+  /**
+   * Filters out entries that are hidden.
+   *
+   * Optionally, it can also filter out entries that are marked as hidden in the strategy options.
+   *
+   * @param {boolean} [applyStrategyOptions = true] If true, entries marked as hidden in the strategy options are also
+   *                                                filtered out.
+   */
+  isNotHidden(applyStrategyOptions: boolean = true): this {
+    const predicate = (entry: T) => {
+      const isHiddenByProperty = 'hidden_by' in entry && entry.hidden_by;
+
+      if (!applyStrategyOptions) {
+        return !isHiddenByProperty;
+      }
+
+      const id = entry[this.entryIdentifier] as keyof StrategyConfig['card_options'];
+      const isHiddenByConfig = Registry.strategyOptions?.card_options?.[id]?.hidden === true;
+
+      return !isHiddenByProperty && !isHiddenByConfig;
+    };
+
+    this.filters.push(this.checkInversion(predicate));
+    return this;
+  }
+
+  /**
+   * Filters entries **strictly** by their `entity_category`.
+   *
+   * - Without `.not()`: returns only entries where `entity_category` exactly matches the given argument (e.g.,
+   *   'config', 'diagnostic', null, or undefined).
+   * - With `.not()`: returns all entries where `entity_category` does NOT match the given argument.
+   *
+   * @param {EntityCategory | null} entityCategory The desired entity_category (e.g., 'config', 'diagnostic', null, or
+   *   undefined)
+   *
+   * @remarks
+   * Visibility via the strategy options:
+   * - If `hide_{category}_entities: true` is set, entries of that category are NEVER kept, regardless of the filter.
+   * - If `hide_{category}_entities: false` is set, entries of that category are ALWAYS kept when filtering for that
+   *   category, even when preceded by `.not()`.
+   * - If neither is set:
+   *   - If preceded by not(), entries of that category are implicitly filtered out.
+   *   - Otherwise they are implicitly kept.
+   *
+   * @example
+   *  .whereEntityCategory('config')           // Only 'config' entries (unless explicitly hidden)
+   *  .not().whereEntityCategory('diagnostic') // All except 'diagnostic' entries
+   *  .whereEntityCategory(null)               // Only entries with 'entity_category: null'
+   *  .whereEntityCategory()                   // Only entries without an 'entity_category' field
+   */
+  whereEntityCategory(entityCategory?: EntityCategory | null): this {
+    const invert = this.invertNext;
+    this.invertNext = false;
+
+    const predicate = (entry: T) => {
+      const category = 'entity_category' in entry ? entry.entity_category : undefined;
+      const hideOption =
+        typeof category === 'string'
+          ? Registry.strategyOptions?.domains?.['_']?.[`hide_${category}_entities`]
+          : undefined;
+
+      if (hideOption === true) {
+        return false;
+      }
+
+      if (hideOption === false && category === entityCategory) {
+        return true;
+      }
+
+      return invert ? category !== entityCategory : category === entityCategory;
+    };
+    this.filters.push(predicate);
+    return this;
+  }
+
+  /**
+   * Sort the entries based in priority order of the provided keys.
+   *
+   * @template K A key to sort by, which must be a key of the registry entry types.
+   * @template T The specific type of RegistryEntry being sorted.
+   *
+   * @param {K[]} keys The keys to sort on, in order of priority.
+   * @param {'asc' | 'desc'} [direction='asc'] The sorting direction ('asc' for ascending, 'desc' for descending).
+   *
+   * @returns {RegistryFilter<T>} A new RegistryFilter instance with the sorted entries and the current filters.
+   */
+  orderBy<K extends keyof T>(keys: K[], direction: 'asc' | 'desc' = 'asc'): RegistryFilter<T> {
+    const getValue = (entry: T, keys: K[]): unknown => {
+      for (const k of keys) {
+        const value = entry[k];
+
+        if (value !== null && value !== undefined) {
+          return value;
+        }
+      }
+
+      return undefined;
+    };
+
+    const sortedEntries = [...this.entries].sort((a, b) => {
+      const valueA = getValue(a, keys);
+      const valueB = getValue(b, keys);
+
+      if (valueA === valueB) {
+        return 0;
+      }
+
+      const ascendingMultiplier = direction === 'asc' ? 1 : -1;
+
+      if (valueA === undefined || valueA === null) {
+        return ascendingMultiplier;
+      }
+
+      if (valueB === undefined || valueB === null) {
+        return -ascendingMultiplier;
+      }
+
+      if (typeof valueA === 'string' && typeof valueB === 'string') {
+        return valueA.localeCompare(valueB) * ascendingMultiplier;
+      }
+
+      return (valueA < valueB ? -1 : 1) * ascendingMultiplier;
+    });
+
+    const newFilter = new RegistryFilter(sortedEntries);
+
+    newFilter.filters = [...this.filters];
+
+    return newFilter;
+  }
+
+  /**
+   * Takes a specified number of entries from the beginning of the filtered results.
+   *
+   * @param {number} count The number of entries to take. If negative, defaults to 0.
+   */
+  take(count: number): this {
+    const safeCount = Math.max(0, count);
+
+    this.filters.push((_, index: number) => index < safeCount);
+
+    return this;
+  }
+
+  /**
+   * Skips a specified number of entries from the beginning of the filtered results.
+   *
+   * @param {number} count The number of entries to skip. If negative, defaults to 0.
+   */
+  skip(count: number): this {
+    const safeCount = Math.max(0, count);
+
+    this.filters.push((_, index: number) => index >= safeCount);
+
+    return this;
+  }
+
+  /**
+   * Applies all the accumulated filters to the entries and returns the resulting array.
+   *
+   * @remarks
+   * - This method creates a forked (shallow-copied) RegistryFilter instance to ensure immutability.
+   * - The original `entries` and `filters` arrays are not mutated or affected by this operation.
+   * - This allows chainable and reusable filter logic, so you can call additional filtering methods on the original
+   *   instance after calling this method.
+   */
+  toList(): T[] {
+    const fork = new RegistryFilter(this.entries);
+
+    fork.filters = [...this.filters];
+
+    return fork.entries.filter((entry, index) => fork.filters.every((filter) => filter(entry, index)));
+  }
+
+  /**
+   * Applies all the accumulated filters to the entries and returns the first remaining entry.
+   *
+   * @remarks
+   * - This method creates a forked (shallow-copied) RegistryFilter instance to ensure immutability.
+   * - The original `entries` and `filters` arrays are not mutated or affected by this operation.
+   * - This allows chainable and reusable filter logic, so you can call additional filtering methods on the original
+   *   instance after calling this method.
+   */
+  first(): T | undefined {
+    const fork = new RegistryFilter(this.entries);
+
+    fork.filters = [...this.filters];
+
+    return fork.entries.find((entry, index) => fork.filters.every((filter) => filter(entry, index)));
+  }
+
+  /**
+   * Applies the filters on a forked instance and returns the single matching entry.
+   *
+   * @remarks
+   * - This method creates a forked (shallow-copied) RegistryFilter instance to ensure immutability.
+   * - The original `entries` and `filters` arrays are not mutated or affected by this operation.
+   */
+  single(): T | undefined {
+    const fork = new RegistryFilter(this.entries);
+
+    fork.filters = [...this.filters];
+
+    const result = fork.entries.filter((entry, index) => fork.filters.every((filter) => filter(entry, index)));
+
+    if (result.length === 1) {
+      return result[0];
+    }
+
+    logMessage(lvlDebug, `Expected a single element, but found ${result.length}.`);
+
+    return undefined;
+  }
+
+  /**
+   * Applies the filters on a forked instance and returns the number of matching entries.
+   * The original RegistryFilter instance remains unchanged and can be reused for further filtering.
+   *
+   * @remarks
+   * - This method creates a forked (shallow-copied) RegistryFilter instance to ensure immutability.
+   * - The original `entries` and `filters` arrays are not mutated or affected by this operation.
+   */
+  count(): number {
+    const fork = new RegistryFilter(this.entries);
+
+    fork.filters = [...this.filters];
+
+    return fork.entries.filter((entry, index) => fork.filters.every((filter) => filter(entry, index))).length;
+  }
+
+  /**
+   * Checks the inversion flag set by {@link not} to a filter predicate and applies the inversion if necessary.
+   *
+   * @param {((entry: T) => boolean)} predicate The filter predicate to apply the inversion to.
+   *
+   * @returns {((entry: T) => boolean)} The predicate with the inversion applied, or the original predicate if no
+   *                                    inversion is to be applied.
+   *
+   * @private
+   */
+  private checkInversion(predicate: (entry: T) => boolean): (entry: T) => boolean {
+    if (this.invertNext) {
+      this.invertNext = false;
+
+      return (entry: T) => !predicate(entry);
+    }
+
+    return predicate;
+  }
+}
+
+export default RegistryFilter;
diff --git a/src/utilities/auxiliaries.ts b/src/utilities/auxiliaries.ts
new file mode 100644
index 0000000..233dc55
--- /dev/null
+++ b/src/utilities/auxiliaries.ts
@@ -0,0 +1,38 @@
+/**
+ * Sanitize a classname.
+ *
+ * The name is sanitized by capitalizing the first character of the name or after an underscore.
+ * The underscores are removed.
+ *
+ * @param {string} className Name of the class to sanitize.
+ */
+export function sanitizeClassName(className: string): string {
+  return className.replace(/^([a-z])|([-_][a-z])/g, (match) => match.toUpperCase().replace(/[-_]/g, ''));
+}
+
+/**
+ * Creates a deep clone of the provided value.
+ *
+ * - It uses the native `structuredClone` if available (supports most built-in types, circular references, etc.).
+ * - Falls back to `JSON.parse(JSON.stringify(obj))` for plain objects and arrays if `structuredClone` is unavailable
+ *   or fails.
+ *
+ * @template T
+ * @param {T} obj - The value to deep clone.
+ * @returns {T} A deep clone of the input value, or the original value if cloning fails.
+ */
+export function deepClone<T>(obj: T): T {
+  if (typeof structuredClone === 'function') {
+    try {
+      return structuredClone(obj);
+    } catch {
+      // Ignore error: fallback to the next method
+    }
+  }
+
+  try {
+    return JSON.parse(JSON.stringify(obj));
+  } catch {
+    return obj;
+  }
+}
diff --git a/src/utilities/debug.ts b/src/utilities/debug.ts
new file mode 100644
index 0000000..df09a11
--- /dev/null
+++ b/src/utilities/debug.ts
@@ -0,0 +1,93 @@
+import { deepClone } from './auxiliaries';
+
+/**
+ * Log levels for the debug logger.
+ *
+ * - Off:   Logging is disabled.
+ * - Debug: Diagnostic information that can be helpful for troubleshooting and debugging.
+ * - Info:  General information about the status of the system
+ * - Warn:  Signal for potential issues that are not necessarily a critical error.
+ * - Error: Significant problems that happened in the system.
+ * - Fatal: severe conditions that cause the system to terminate or operate in a significantly degraded state.
+ */
+export enum DebugLevel {
+  Off = 0,
+  Debug = 1,
+  Info = 2,
+  Warn = 3,
+  Error = 4,
+  Fatal = 5,
+}
+
+/**
+ * Individually exported log level constants.
+ *
+ * @see DebugLevel
+ */
+export const {
+  Off: lvlOff,
+  Debug: lvlDebug,
+  Info: lvlInfo,
+  Warn: lvlWarn,
+  Error: lvlError,
+  Fatal: lvlFatal,
+} = DebugLevel;
+
+/**
+ * The current global log level.
+ *
+ * Only messages with a level less than or equal to this will be logged.
+ *
+ * @default DebugLevel.Off
+ */
+let currentLevel: DebugLevel = DebugLevel.Off;
+
+/**
+ * Sets the global log level.
+ *
+ * @param {DebugLevel} level - The maximum level to log.
+ * @see DebugLevel
+ */
+export function setDebugLevel(level: DebugLevel) {
+  currentLevel = level;
+}
+
+/**
+ * Logs a message in the console at the specified level if allowed by the current global log level.
+ *
+ * Only messages with a level less than or equal to the currentLevel are logged.
+ *
+ * @param {DebugLevel} level - The severity of the message.
+ * @param {string} message - The message to log.
+ * @param {unknown[]} [details] - Optional extra details (e.g., error object).
+ *
+ * @throws {Error} After logging, if the level is `Fatal` or `Error`.
+ */
+export function logMessage(level: DebugLevel, message: string, ...details: unknown[]): void {
+  if (currentLevel === DebugLevel.Off || level > currentLevel) {
+    return;
+  }
+
+  const frontEndMessage: string = 'Mushroom Strategy - An error occurred. Check the console (F12) for details.';
+  const prefix = `[${DebugLevel[level].toUpperCase()}]`;
+  const safeDetails = details.map(deepClone);
+
+  switch (level) {
+    case DebugLevel.Debug:
+      console.debug(`${prefix} ${message}`, ...safeDetails);
+      break;
+    case DebugLevel.Info:
+      console.info(`${prefix} ${message}`, ...safeDetails);
+      break;
+    case DebugLevel.Warn:
+      console.warn(`${prefix} ${message}`, ...safeDetails);
+      break;
+    case DebugLevel.Error:
+      console.error(`${prefix} ${message}`, ...safeDetails);
+      throw frontEndMessage;
+    case DebugLevel.Fatal:
+      console.error(`${prefix} ${message}`, ...safeDetails);
+      alert?.(`${prefix} ${message}`);
+      throw frontEndMessage;
+  }
+}
diff --git a/src/utilities/localize.ts b/src/utilities/localize.ts
new file mode 100644
index 0000000..35bc8f1
--- /dev/null
+++ b/src/utilities/localize.ts
@@ -0,0 +1,74 @@
+import * as de from '../translations/de.json';
+import * as en from '../translations/en.json';
+import * as es from '../translations/es.json';
+import * as nl from '../translations/nl.json';
+import { HomeAssistant } from '../types/homeassistant/types';
+import { logMessage, lvlWarn } from './debug';
+
+/** Registry of currently supported languages */
+const languages: Record<string, unknown> = {
+  de,
+  en,
+  es,
+  nl,
+};
+
+/** The fallback language if the user-defined language isn't defined */
+const DEFAULT_LANG = 'en';
+
+/**
+ * Get a string by keyword and language.
+ *
+ * @param {string} key The key to look for in the object notation of the language file (E.g., `generic.home`).
+ * @param {string} lang The language to get the string from (E.g., `en`).
+ *
+ * @returns {string | undefined} The requested string or undefined if the keyword doesn't exist/on error.
+ */
+function getTranslatedString(key: string, lang: string): string | undefined {
+  try {
+    return key.split('.').reduce((o, i) => (o as Record<string, unknown>)[i], languages[lang]) as string;
+  } catch {
+    return undefined;
+  }
+}
+
+/**
+ * Singleton instance of the localization function.
+ *
+ * This variable is set by {@link setupCustomLocalize} and used by {@link localize}.
+ *
+ * - Must be initialized before {@link localize} is called.
+ * - Holds a closure that translates keys based on the language set during setup.
+ *
+ * @private
+ */
+let _localize: ((key: string) => string) | undefined = undefined;
+
+/**
+ * Set up the localization.
+ *
+ * It reads the user-defined language with a fall-back to English and returns a function to get strings from
+ * language-files by keyword.
+ *
+ * If the keyword is undefined, or on error, the keyword itself is returned.
+ *
+ * @param {HomeAssistant} hass The Home Assistant object.
+ */
+export default function setupCustomLocalize(hass?: HomeAssistant): void {
+  const lang = hass?.locale.language ?? DEFAULT_LANG;
+
+  _localize = (key: string) => getTranslatedString(key, lang) ?? getTranslatedString(key, DEFAULT_LANG) ?? key;
+}
+
+/**
+ * Translate a key using the globally configured localize function.
+ * Throws if not initialized.
+ */
+export function localize(key: string): string {
+  if (!_localize) {
+    logMessage(lvlWarn, 'localize is not initialized! Call setupCustomLocalize first.');
+
+    return key;
+  }
+  return _localize(key);
+}