Blender is far better than anyone not-in-the-know would expect.

VLC does much more than just play videos, but the user interface inexplicably hides most of the functionality. Also, they’ve vehemently claimed for many years that it’s impractical to provide backward frame-by-frame stepping, but Celluloid does it just fine.

GIMP and Inkscape keep improving, with GIMP being the better of the two. GIMP should just copy Photoshop’s interface as closely as possible. There’s no shame in that, and Photoshop does many things better. Most users coming to GIMP are coming from Photoshop. (Yes, I’m using PhotoGIMP, but that really doesn’t do much to help.)