Usually, fanfics portray Foggy as the caregiver in their relationship (and I love that!), but to me it's clear from their interactions in the show that Foggy also feels grateful for Matt, and I would like to read something that explores those feelings!
Show me some of the things, big and small, that Matt has done for Foggy or still does for him on a regular basis. Little favours, emotional support, gestures of affection, adjustments and compromises, just generally taking care of him when he needs it etc.

I'd like a sprinkle of romance to go with my fluff, but friendship would be fine, too! (Or pining. I'm always here for not-actually-unrequited pining.)