June Something Day 13

What do YOU consider fandom's "little black dress"? Is it a coffeeshop AU? Sharing a bed trope? Bonus, share your favorite example.

While I do love a good coffee shop AU, I have to go with Sentinel AUs. I love them so damn much! Two of my favorites are by esteefee:

Mosquito, Gnat, and Midge Season where John is with the FBI, Rodney's a French Canadian Mountie, and neither one is all that happy with the whole Sentinel/Guide thing or with each other. Hilarity ensues!

And Redemption where Sentinels are second class citizens and almost anyone can be a Guide--if they want. Rodney gets roped into helping John, who insists that he's not a baby duck!

I do love how much fun these fusions can be, especially when the author shows how being a Sentinel or Guide is just that something extra that makes life...interesting. :D