Soulmate au where Foggy realizes when they first meet that him and Matt are soulmates (he sees colors or they have matching marks or whatever) and actually TELLS Matt like, 'hey, dude, you're totally my soulmate'

Matt (for whatever reason) doesn't exactly believe him so Foggy's like 'fine, be that way, i'll prove it to you'

And then Foggy just proceeds to BE FOGGY until one day Matt has an epic realization and goes 'holy shit, you really are my soulmate'