Valve Community

Team Fortress HQ provides the latest news, articles, skins, maps, sprites, and everything else Team Fortress you can imagine.

Stu-Pidaso is a website aimed at Half-Life and everything related to it.

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

“Official website set up to accomodate Garry’s Mod related downloads without waits.”

The L4D Map Database is a library of all Left 4 Dead maps (official and custom) in the form of a wiki that anyone can contribute to. Includes downloads, screenshots, videos, information, and more for each map.

PCosmos is a great list of Half-Life maps and mods. It is also available in French.

Modifikace is a Czech news and review site for single player Half-Life 1.

Map-Factory is a database hosting custom maps for any FPS. If you’ve make a map or simply came across a good map, feel free to submit it! If not, then just navigate through the site and you’ll find a lot of good maps!

City 17 is a Russian review site for single player maps and mods.

My Aperture Labs: Welcome to the Aperture Science Enrichment Center’s Online Community Networking Web Service (or ASECOCNWS for short). Here at the ASECOCNWS, test subjects may attempt to solve Portal puzzles, build their own Portal puzzle environments, or simply talk about cake.

Ten Four is a well known single player review site that covers a few different games. They present 3 levels of awards for the better releases and the forum, whilst not as busy as they used to be, is still a place to find the latest releases.

TF2Portal.es is a spanish website focused on Team Fortress 2. Some of the contents are: news, downloads, tutorials, forums and a public server.
TF2Portal.es es una web en español dedicada por completo a Team Fortress 2. Algunos de sus contenidos son: noticias, descargas, tutoriales, foros, y un servidor público.