Half Life Storm contains forums for discussions about the Half Life Series and the other Source Engine games by Valve. It is mainly directed towards mapping, as it contains many mapping tutorials. It will expand into other categories later on.

Half-Wit 2 is packed with tutorials, guides and other useful bits of information to help anyone creating custom content for the Source Engine. There is plenty of good stuff here and well worth checking out.

HalfeR is a Russian fan-site, specialized on Half-Life, Half-Life 2, Episodes, addons like Blue Shift, Opposing Force and huge modifications like Black Mesa: Source and so on. The site contains news, previews, reviews, interviews, screenshots, patches, etc. fixes about the games.

Halflife2.net features information about all Valve titles, as well as the largest Valve forum community outside of Steam. It is a good resource for news and general information about the games, and the community can answer most Half-Life related question. The site is hosted and supported by Valve themselves.

Headcrab.pl is a Polish website that covers most of Valve’s newer games.

HL Gaming covers all the news related to Valve gaming, including TF2, L4D and all your HL favourites.

Half-Life Portal is the biggest German website for Half-Life games, mods and other games from Valve. This web-portal has a community with forums, many news, articles, downloads and informations regarding most of Valve’s games, as well as Steam and third-party Source Engine games.

HL Site is a Russian portal for some of Valve’s games.

HL2Mods is a simple and easy to use directory of mods for Half-Life 2. It covers Episode One and Two but doesn’t make a distinction.

HL2Spain is a Spanish fan-site and gaming community covering everything about the Steam Platform, Valve Games, and Source Engine based Games & MODs. It includes news, reviews, previews, manuals and tutorials done by their team and the community itself.

HL2World.com is a news and forum based site that has been around for a long time. The forum is particularly active.