Add fields for external video game database ids. This would be helpful for developers to pull additional data from other databases.
Take for example, platforms. Each platform has an ID on other databases (screenscraper, mobygames, thegamesdb, launchbox). Same for games.
The field should allow a list entry as one game on IGDB might be multiple ids on a different database if they don't combine games from different platforms into a single entry like IGDB does.