Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
Voxel Builder - Design and edit 3D voxel models in your browser.
Pixel Art to CSS - Draw and animate pixel art, export the results to CSS
Pixilart - A drawing app for delightfully retro pixel art
Pixel Art Studio - A purpose-built drawing tool for pixel artists
Da Vinci Eye - Learn to draw by using your phone to overlay images for you to trace