Sprite Fusion - Design your game with Sprite Fusion, the ultimate free online tilemap editor. Design 2D games with ease, direclty export to Unity Tilemap and Godot Scenes. Ideal for retro games!
Jpixel - JPixel is an editor for making pixel art animations and tilesets.
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
Synfig Studio - Just another WordPress site
LibreSprite - Free and open source program to create animated sprites.
DragonBones - DragonBones is an open source project for 2D skeletal animation.