Blender.

3D modelling, UVs, texturing, animation, video editing, compositing, motion graphics, motion tracking, 2D animation, and a fucking powerful render engine? Check.
Great community? Check.
Powerful and easy scripting system? Check.
A well organized dev team? Check.
People who care about UI/UX? Check (look at Blender 2.8).
Does it compete with a major corporation that would go into sloth otherwise? Check. (If you thought M$ was shaftware wait till you see Autodesk)

There are other FOSS projects that I really like, but my vote definitely goes to Blender.