Paint illustrations and concept art with custom brushes and layers.
Free desktop download; commercial use allowed. No image quota; optional store editions are paid.

Design & creative
Draw traditional frame-by-frame 2D animations.
Draw traditional frame-by-frame 2D animations.
Draw traditional frame-by-frame 2D animations. See limitations before switching.
For hand-drawn animation, not Animate interactive projects or ActionScript.
Each comparison covers the workflow described above, rather than every paid feature.