A little web directory of game engines and tools
Round, flat, designer-friendly
pseudo-3D engine for canvas & SVG
A regular source is The Candybox Blog.
Contains information about 1368 open source games and 310 game engines/tools.
A collection of free software and free culture resources for making amazing games.
A collection of high-quality, free, online creativity tools.
A huge source of links is always Game Developer: The Art and Business of Making Games.
The Art and Business of Making Games