Chaotic Cosmos, a classic Gundam SEED fanfic. While its a million words long and contains a ton of fanwanky stuff in it, the new set of BCPUs and the inclusion of newtypes among other things; the writing is great enough that I honestly didn't mind it at all during my first read of it, that and said fanwanky villains start getting more interesting and fun to read later on as the author starts getting more used to their characterization.