TexturePacker - Texture Packer is hands down the best sprite sheet generation tool on the market.
Commandline Challenge - Test your command line skills
Free Texture Packer - Free Texture Packer is an open source tool that allows you to pack multiple images into one atlas for you games or sites.
Prompt - Prompt provides fully-integrated writing education solutions, combining instruction, curriculum, and feedback. We support educational institutions, companies, and individuals.
Sprite Sheet Packer - Sprite Sheet Packer is online that you can easily use to pack sprite sheets, including data formats for CSS, LESS, and Phaser.
Cwiki - A Command line interface for searching Wikipedia!