While playing Brotherhood, one particular scene made me imagine a MLP crossover. Near the end of Sequence 2, Niccolo and Ezio were discussing how to confront Chesere...

and at 3:35, I started imagining Applejack as a mercenary, Rarity a a Courtesan, RD as a thief, etc. Did an internet to see what's already out there, and found this group.