Pixel Art Studio - A purpose-built drawing tool for pixel artists
Pixel Art to CSS - Draw and animate pixel art, export the results to CSS
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
JS Paint - JSPaint is a web-based Microsoft Paint remake
Pixel Art Together by Liveblocks - Pixel Art Together is a multiplayer pixel art editor, allowing up to 20 people to create art on the same canvas, at the same time.
KiddoPaint - MS Paint in your browser (with emojis 💃😽🎨)