Analog Game Studies: As the name implies, this is a journal dedicated to writings on analog games. Divided into three sections – “analysis,” “documentation,” and “experimentation & design” – each issue contains three articles. A useful & interesting resource if you’re interested in the analog side of gaming.
BoardGameGeek: A great resource for (as you might guess!) board games. Some of the user-submitted content is excellent, and the site offers overviews of everything from ancient games to the latest releases.
The Console Living Room (Internet Archive): An amazing example of software archiving, The Console Living Room is a digital collection of home consoles (and a few handhelds), with a great many playable (in your browser!) games.
Critical Distance: C-D brings together some of the more interesting, thoughtful, and unique writing on games each week. There are also curated collections related to specific games, as well as a podcast.
The Digital Games Research Association (DiGRA): DiGRA is one of the main associations for academics & professionals who research digital games. You can access the digital library and the Transactions of DiGRA (ToDiGRA) journal.
GameSetWatch: Now defunct (though the archives are intact) little sibling to Gamasutra; the archives (particularly the columns) are worth poking through.
GDC Vault: The Game Developers Conference (GDC) comprises several conferences – these are some of the premier events for the (digital) game industry. The GDC Vault includes the conference presentations, talks, and panels – many of which are available for free.
The Internet Arcade (Internet Archive): Another example of pretty amazing software archiving, the Internet Arcade is another digital collection with many playable games.
Leigh Alexander: A selection of writing by Leigh, whose writing I have enjoyed for a long time (a good place to get ideas about thoughtful, but non-academic, writings on games & media generally)
Memory Insufficient: A games history ezine with a wide range of thoughtful essays. Published approximately once a month, it’s another good place to hunt for interesting articles on everything from ancient boardgames to videogames.
MS-DOS Games (Internet Archive): Like the Internet Arcade & Console Living Room, you’ll find a large collection of (playable in your browser!) MS-DOS games – including some real classics from several genres. There is also a showcase highlighting games of particular interest.