A list of free game libraries : Free Game Libraries
You are still here instead of going to the link .
Even though the list hasnt been updated in a long time, its still the most complete list I have found. There are a ton of entries, and I would say it is pretty comprehensive. It would be nice, if it mentioned if the link/library was still active but you cant win them all.
This site breaks entries down into their general category ( 3D Graphics, 2D Graphics, Sound/Music, Networking, Video, Compression, Artificial Intelligence, Math/Physics, Scripting, etc. ), each entry contains a link to the library as well as the license it was released under
