This list also include open source games with non-free data.
Non-free data games will be marked accordingly.

Additional resource:
https://libregamewiki.org/Main_Page (only full libre game, including the art assets)
https://osgameclones.com/ (open source game clone list)
https://trilarion.github.io/opensourcegames/ (open source game list)
https://en.wikipedia.org/wiki/List_of_open-source_video_games (English wiki)