Sorry for the slow replies. It's convention crunch time for me, hahaha.

As for AU types, there are plenty of them! Just kind of depends on what kind of settings you like or what you'd think would work with Tamaki best. My weaknesses are medieval AUs; and I have to admit I have a thing for fealty, certainly. An idea could be that Tamaki is a prince and Kyouya is a loyal servant or knight.

Or it could be modern day AU where they're royalty from different countries and their relationship unwittingly blossoms into romance. Really, anything is game!