CSS Sprite Generator - A tool for generating image sprites and CSS for your web site.
SpritePad - The easiest way to create your CSS sprites
SpriteSheep - SpriteSheep lets you easily and visually generate CSS sprite sheets and CSS code with all sprites...
Spritesheet - CssSpriter is a small utility (with a nice graphical user interface) to create css sprite sheets from multiple icons (like icons, buttons, ....
PICO-8 - Lua-based fantasy console for making and playing tiny, computer games and programs.
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.