After the amazing Arx Fatalis engine open-sourcing, I noticed the source/asset release of Bikez II, which is a city-driving-fighting game built on DirectX. 3D models are in the 3dw format (no idea what that is).
Unknown Worlds' icons
I mentioned the developer of Bikez II in a talk on open game development marketing last week (not directly related to open *source*). One of the other developers I was talking about, Unknown Worlds (working on proprietary Natural Selection 2) have released some of their tools under BSD license: an updater library and an icon set.
I wonder what other freely licensed gifts lie around in indie developer's archives and wikis.
Somehow I found Screenkey, which shows key presses and could be used for making asset video tutorials and such.