Impressive list, I haven't heard about SoulFu and looks very well.

Let me add a few more of which I haven't seen any post yet:

Speed Dreams
http://speed-dreams.sourceforge.net/
Speed Dreams is a fork of the famous open racing car simulator TORCS, aiming to implement exciting new features, cars, tracks and AI opponents to make a more enjoyable game for the player, as well as constantly improving visual and physics realism.

Secret Maryo Chronicles
http://www.secretmaryo.org/
Secret Maryo Chronicles is an Open Source two-dimensional platform game with a design similar to classic computer games. SMC has computer support to a great degree by using an accelerated Open Graphics Library for the best possible graphic design and stock performance.