There are not so many sites offering problem collections:

• mainly uliGo, where some of the collections of Drago installation have been found. It offers also classical problem collections and the uliGo program to solve problems.
• GoProblems enabling to solve and add problems online, and enabling to download the complete collection.
• GoCollections enabling to share problem collections proposed by the site users
• See also the link page of the British Go Association

You can also subscribe to the Tsumego mailing list to receive each week Life&Death problems of all levels, proposed by Fan Hui, 2p, strongest rated player living in Europe.

Game collections are easier to find:

• the complete collection of Cho Chikun games is at My Friday Night Files :: Cho Chikun ::
• the complete collection of Go Seigen games is at ByHeart with other collections of classical or modern Go players (Takemiya, Lee Changho)
• and also Professional Games in Smart Go Format, go games ...
• A very big (several dozens of thousand) collection of games played on KGS by 6d and 7d players is available in Kombilo website.
• Take a look also at the link page at Sensei'Library to get a complete list of available game databases (free or not, commented, online, ...)

Here are the links to two very useful SGF files:

• The joseki database of Kogo's Joseki Dictionary
• The fuseki database of arno's Fuseki Database

Games of Go On Disk (aka GoGoD) offers on CD a huge collection of pro games (almost 50 000), but also an inexhaustible encyclopedia related to Go.

Go4Go where you can subscribe to get their whole game collection, plus weekly updates. Go4Go offers also to download freely single games. Very recent games are available with day by day updates.

GoBase is another great only resource, although the subscription is not free anymore.