I collected technical infos about more than 500 open source games and put them in a Github repository (game entries in text format). A dynamic HTML table of the entries is created from the data. It allows search and sorting. For all the games there is a link to the game homepage and the sources. Partly there are platform info or build info. I plan to add more games and fill in more info. I also converted some old CVS, SVN repositories to Git and put them on Gitlab.com/osgames. A game statistics page is automatically compiled about the games. It might be interesting to see what is out there, maybe get inspired by an idea. Suggestions for additions are always welcome.

Thanks for the appreciation. Unity is indeed very popular. You can get some open source replacements for it like libGDX, Monogame, Godot engine or some 3D frameworks like Urho3D, Panda3D, ... but they are all either less comprehensive, less practical to use or less OS independent. I'm personally more interested in the ideas behind the games. Converting them from one platform to another is usually possible one way or the other.

Back in the day I released the full code for The Insulines made with Moai.  https://github.com/the-insulines

Just in case you wanted to add it to the list

Thanks for the suggestion. Btw. I'm now over 800 entries.