If you haven’t guessed already, I kind of love Kurt and Blaine. Here are some lovely fanfic recommendations!
Where There’s Smoke by stoney321 (Fireman AU. Absolutely beautiful)
The Bones of You by stoney321 (Kurt and Blaine have broken up, but there paths cross again a few years after college)
Art or Nothing by Walcott (AU in which Kurt is an art student and Blaine is a figure model. Sounds like smut, but actually, it is one of the sweetest, most innocent pieces I have ever read).
Taking Root by hellonik (a beautifully written CrissColfer story in three parts)
Syrup & Honey by heartsmadeofbooks (a fluffy and lovely Kurt and Blaine AU in which Kurt owns a bakery, Blaine is a lawyer, and they fall in love)
More to be added!