This is the stuff I use for 3D images and games, there are other items, but they are less in the spirit of FOSS than they are just free versions of more robust programs (Sculptris, for example.) I threw the game stuff in here, though it doesn’t strcitly fit the 3D bill, I’m just starting out on trying Blender’s Game engine.
3D Art and Game Programming – Makes fun stuff
Blender -> Replaces Maya / 3DS Max / Unity (sorta) / Adobe After Effects & Premiere (sorta)
Blender is probably my personal favorite from this list. This plucky 3D graphics render program is a lot of bang for a single piece of software. If you aren’t into 3D rendering, the video editing tools are still good enough to pull your attention. I’ve been able to do nearly all my learning about how to use this program (with a tremendously steep learning curve for those not used to 3d rendering) online for free. The resources are out there, and the community is fantastic. Add to this, the fact that you can write scripts in Python for the program, and you have me sold. The game engine is not half bad, it probably can’t compete with Unity (also free) yet, but it is open source.
MakeHuman -> Procedurally generate human models
MakeHuman exports to a format useable by all 3d rendering programs, and dramatically reduces setup time for people images. Incredibly valuable for 3D artists who aren’t great modelers, but want to make images of people.
PyGame -> Versatile game coding for python
PyGame is a great framework for creating simple games in Python. Combined with other resources, it can be a really powerful engine builder, and it plays very well with Blender.