LibreSprite: make a short blinking-light study
A tool entry with a small animation exercise and its official source.
LibreSprite is a free, open source sprite editor. Its official repository describes layers, frames, onion skinning and a live animation preview: https://github.com/LibreSprite/LibreSprite .
A manageable first exercise is a 24×24 desk lamp in three frames: bright, dim and bright again. Keep the base and shade still. Change only a few pixels near the bulb so the motion has one clear cause.
Compare the frames at normal display size before adding extra glow. This is an exercise proposal, not an animation file or a claim that every export format fits every game.