Another moment in my love affair with story form!! I just finished David Levithan's The Lovers Dictionary, a quick little story, but one that keeps lingering in my head.
As it says on the tin, it is a dictionary, with alphabetically ordered words as headers followed by short moments that describe a relationship in the context of the word - or in opposition in some cases, underlining the point being made. As a reader you savour the associations between single words and ordinary moments in life as they come together as a definition.
It isn’t long, but that just proves that a few words can go far. (Top skills, Mr Levithan!) It isn’t a linear story either, but it gives you a rounded view of the relationship they have. I say “they”, as this is another quirk of the story; there is no indication of the gender/s of either "you" or "I".
Apparently Levithan wrote the first draft of this as a Valentine to his friends. I don't know if that qualifies it as a card as well form-wise, but I enjoyed it for that too.