LibreSprite is a free and open source program for creating and animating your sprites. Real-time animation previews. Onion skinning. Multiple sprites can be edited at once. Ready to use palettes, or make your own. Sprites are composed of both layers and frames. Tiled drawing mode, useful to draw patterns and textures. Pixel precise tools like filled contour, polygon, shading mode, etc Several file types supported for your sprites and animations.

A Pixel Art Editor. Self hosted. Single page app. Draw old-school pixel art by hand in your web browser, save the images locally. Can assemble frames into an animated gif. Can even import an image file and turn it into an approximate pixel art image. Can be installed as a progressive web app but good luck getting those to work.

The collaborative, web-based, massively multiplayer game Glitch began its initial private testing in 2009, opened to the public in 2010, and was shut down in 2012. It was played by more than 150,000 people and was widely hailed for its original and highly creative visual style.

The entire library of art assets from the game, has been made freely available, dedicated to the public domain. (CC0)

Classic video game sprites of all kinds can be found here. They make great icons.

A webapp and desktop vector drawing application that uses a grid of dots as a backdrop for sketching. Connect the dots and it makes the lines for you. Designed with logos and sprites in mind. Saves PNG and SVG files. Cross platform.