http://www.fimfiction.net/story/151748/voyages-end
https://www.fimfiction.net/story/159150/the-eagle-has-landed
http://www.fimfiction.net/story/219586/lunas-return-trajectory
http://www.fimfiction.net/story/24178/across-the-universe
Mass Effect crossover:
http://www.fimfiction.net/story/299981/why-no-one-messes-with-celestia