You'll Never Fit In Much, Kid - CosmicZombie ( http://www.ficwad.com/story/149429 )
Trying To Escape The Inevitable - CosmicZombie ( http://www.ficwad.com/story/173331 )
First Of The Gang To Die - Unitedsuck007 ( www.ficwad.com/story/160600 )
These are all good, but I would say First Of The Gang To Die. It's fantastic. A quick summary of it would be that it's frank and Gerard based in the 1930's mafia. It's really gorey, bloody, violent. There is some scenes of rape and abuse, but not between frank and Gerard. It's can get really fluffy and cute too. It's about 86 chapters and it is very long. Might take you a few days to finish reading.
All of them are good so you should read them all if you get a chance.