Game Developers Conference records, must see for any game designer. Big part of the content is paid, though. But even in the free part, you will find a lot of useful knowledge.
The biggest game industry online professional community. News, articles, blogs, forums, jobs, and many more.
Game Designers Vault
Great place for game design beginners, with a lot of useful links and tutorials.
If you’re looking for some academic knowledge about game design, this is the place. Just search “Game Design”.
Digital Games Research Association – another good source of the academic knowledge about games and game design.
One of the best sources of information about the business side of the game industry.
One of the best sources of information about game market trends and research data. Detailed reports are paid.
Great source of the mobile game market research and data.
Free courses from the world’s top universities (game design courses included). If you’re looking for the source of fundamental knowledge in different areas, this is the place.
The best-known place, if you’re looking for new ideas, knowledge or just want some inspiration.