Magical Girls in my Magical Boys Anime?!
This character is a mascot in a recent Magical Girls AU.
Jack
This silly AU quickly devolved in human experimentation, now existing as one of the longest forum threads on the server.
The fandom there are the most crossovers for in the forum.
Pokémon
The largest (in message count) time travel AU on the server.
Hit by a love potion, this character is fluffy, lovey-dovey and adorably clingy to everyone as they deal with a prolonged fever.
Ace
These two characters show up frequently in the cast of Magical Girls AUs, often against the will of the creators.
Ace and Kalim
This character ended up being forgotten by the cast, existing as a (metaphorical) ghost on campus grounds.
Jack
This crossover features a pair that is engaged to each other and excitedly awaiting their marriage.
Ace and Sebek / Heart of a Butterfly Brother
In this AU, the main character manages to remove himself from the storyline.
Imprint of You / Ace Deletes Himself
In this AU, one character keeps leaving holes in the walls in their haste to reach princesses.
Princess Snatching AU (Or, that Malleus that hoards princesses)
In this AU, six characters were kidnapped pre-canon and taken as experiments.
Lab Grown Magical Girls AU
The entire student base of Scarabia in this AU is dead- other than Kalim, who is stuck in a coma.
For the Want of a Nail
In this AU, the basketball club has been getting up to some fun thievery shenanigans.
Take Over- Basketball Style
Several characters in this AU have journeyed back in time from the worst future imaginable, and are now terrified of ink.
Back Again: For the Want of a Nail. (FTWOAN is also accepted as a standalone answer).
These five characters snuck into NRC to attend school, crossdressing the entire time.
Ace, Ruggie, Kalim, Rook and Sebek
For this group of magical girls, God takes an unexpected form...
A Basketball
Genocide is an ongoing issue in this AU, as a select demographic of people is continually massacred by the government and society.
Synecdoches AU
The power of crossdressing lesbianism saves the day!
Punk x Otaku
In this AU, Leona is always held back a year in NRC. Every single time.
Time Loopers Magical Toddlers AU
This character was discovered dead three times during a party.
Cater
This AU is the origin of the server passion for an uncommon rarepair.
In this AU, Lilia cut his hair for the final time due to Floyd thinking it would make a delicious snack. It now remains short.
Swinging Mentor
This character, featured in the Twisted Pokémon AU, shows up in the form of Yveltal.
Floyd
In this AU, this minor character was assassinated, changing an entire dorm's living situations.
Falena - Rewritten History and Time Traveller First Years AU
In this AU, Vil's skincare products being misused accidentally caused the start of the major plotline.
Crack Vampire Werewolves AU