Aseprite
Aseprite combines pixel-precise drawing, layers and frames, tags, palettes, onion skinning, and sprite-sheet export in a focused workflow.
Why it’s here
Its specialized pixel-animation operations remove a great deal of repetitive setup from characters, effects, and tile production.
Best fit
Art, animation, audio, levels, and narrative turn mechanics into a believable world.
Before you commit
Official binaries are paid; source is visible and may be compiled for personal use, but the Aseprite EULA forbids redistribution of compiled copies.