Graphics Gale - great straightforward workflow for animation, good palette editor. well rounded
Aseprite - the most popular and feature rich pixel art editor, frequent and active development and support
Pyxel Edit - great for working on tiles, can place tiles and editing one edits all on the canvas
Photoshop - best for advanced editing features, blend modes, adjustment layers, smart objects,clipping masks, etc
Pro Motion - arcane and ancient magick