Stargatefan, started in 1997, is a large fansite devoted to Stargate SG-1 and Stargate Atlantis that features fic, art, links, historical information relevant to the show, and other resources for fans. In 2013, the Organization for Transformative Works announced that Open Doors would assist StargateFan in preserving over 2,000 stories, fan art, and comics to their own collection on AO3.
The Good Omens Library: A Nice and Accurate Stories Archive, first opened in 2005 as a hub for Good Omens fanfiction. After eight years, decreased funds and usership nearly closed the archive for good. To preserve its works and allow the collection to continue to grow, it was imported into a new AO3 collection in 2013.
Yuletide is a popular annual rare-fandoms gift exchange fan fiction challenge, encompassing gen, het, femslash, and slash. The idea of Yuletide is to provide fiction for people who may never have seen any stories for a source they love, or have seen so few that they're starving for them.
Importing the Yuletide Archive to the Archive Of Our Own had been planned for a number of years. While the challenge has been operating on the AO3 since 2009, it was not until May 2014 that we were able to actually move the original archive for the years 2003 to 2008.