Spine - Spine is 2D animation software designed specifically for software and game development.
ShoeBox - Free unlimited photo storage, so you can rediscover your photos anywhere. Available for iPhone, iPad, Android, Mac and PC.
Synfig Studio - Just another WordPress site
TexturePacker - Texture Packer is hands down the best sprite sheet generation tool on the market.
Unity 2D - Unity 2D is a powerful and feature-rich game design solution built from the ground up to fulfill every basic and advanced need of the developer.
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.