MobyGames

IGDB (Internet Games Database) is an online database of video-game metadata and a developer-facing API, maintained by Twitch (acquired 2019). It provides structured information on games — including titles, platforms, release dates, genres, themes, companies, cover art, screenshots, videos and external IDs — and exposes that data via a REST API that uses Twitch developer authentication and terms of use.

RomM is a self-hosted ROM manager and player for organizing an owned game collection. It scans game folders, parses filename tags and naming schemes, and enriches entries with metadata from IGDB, Screenscraper, and MobyGames, with artwork from SteamGridDB. The interface supports metadata for more than 400 platforms, custom tags, multi-disk games, DLCs, mods, hacks, patches, and manuals. RomM can display RetroAchievements progress and play compatible games in a browser through EmulatorJS and RuffleRS. It supports browsing, uploading, updating, and deleting games through a web browser, sharing a library with limited permissions, and official apps or integrations for Playnite, Android, and custom firmware handhelds.

ScreenScraper is a community-run database and media repository for retro video games that collects and redistributes game metadata and media assets under Creative Commons. It provides downloadable media and metadata intended for multi-system gaming front-ends and community projects.

MusicBrainz is an open, community-maintained music metadata database and "open music encyclopedia" operated by the MetaBrainz Foundation that assigns persistent MusicBrainz Identifiers (MBIDs) for artists, releases, recordings, works, labels and release-groups. It publishes regular database dumps and offers a public webservice (JSON/XML REST API) and search endpoints, and ships an official tagging client (MusicBrainz Picard). MusicBrainz integrates with audio-fingerprint services such as AcoustID/Chromaprint for identification and is used for tagging, synchronization, cataloging and lookup by media players, taggers and content services.

RetroAchievements is a community-run website and service that adds modern-style achievements and tracking to classic video games by monitoring in-memory game state via supported emulator clients. It maps achievements to specific game ROMs (checksums), provides per-game achievement lists, user profiles, leaderboards and unlock records, and exposes an online API used by emulator integrations (examples of supported clients include BizHawk and RetroArch).