The Steam Trading Card program, which Valve launched in May, is already coming out of beta. The company announced plans to release the full version on Wednesday at 11 AM PT, along with a large batch of new cards to collect.
Valve announced the plans on its forums. It didn't detail which games will get cards in Wednesday's update, but it did say that "several games" will get the additions instead of the usual, smaller Tuesday and Thursday releases. It also noted that for the time being it is going to be focusing on fixing bugs, pushing extra features like Trade Offers and the Card Binder to an unspecified post-release date.
When the beta launched, cards were supported in Counter-Strike: Global Offensive, Dota 2, Don't Starve, Half-Life 2, Portal 2, and Team Fortress 2. Games have been regularly added since then, for a grand total of more than 30 now. You can check out the full list of supported games and give feedback at the Steam group.