Game UI Wiki is an open collection of game interface screenshots, organised by game and UI screen type. It exists as a reference for designers, developers, students and anyone interested in how games present information to players.
The site was started by Louise McLennan as a personal project and grew into a public resource. It is independently funded and maintained - it is not going anywhere.
Anyone can contribute. If you have screenshots from a game that is not yet covered, create an account and add them. See How to contribute for a guide on getting started.