Pixelorama
A free & open-source 2D sprite editor, made with the Godot Engine
...A variety of different tools to help you draw, with the ability to map a different tool in each left and right mouse buttons. Are you an animator? Pixelorama has its own animation timeline just for you! You can work at an individual cel level, where each cel refers to a unique layer and frame. Supports onion skinning, cel linking, motion drawing and frame grouping with tags. Custom brushes, including random brushes. Create or import custom palettes. Import images and edit them inside Pixelorama. If you import multiple files, they will be added as individual animation frames. Importing sprite sheets is also supported.