What makes a rare pair rare?

[peoriapeoriawhereart]

This time I'm going to be specific, and MCU & Marvel (comics). Keep in mind I was quickly made over as a slasher when I joined the internet's version of media fandom. At the time, that meant my 'ships and canon ships wouldn't even pass in the night.

Stony (aka Steve/Tony) is not a rare pair; it's canon in some multiverse realities, and fandom ran with it when MCU was unformed enough raiding comics canon was common. Stucky (Steve/Bucky) is not a rare pair because fandom ran with it. Pepperoni (Pepper/Tony) I wouldn't consider rarepair, it's MCU on and off and on again canon. Phlint (Phil Coulson/Clint Barton aka Shieldhusbands) is not a rare pair, slashers love that.

Is it a rare pair if it has Clint in it? Natasha/Clint, Bobbi/Clint, Penny/Clint, Spider-Woman/Clint (sorry, too many Jessicas) are all comics canon. Okay, arguably Winterhawk (Bucky/Clint) and Frosthawk (Loki/Clint) are rare pairs.

And yes, it does say something about fandom that I'm in the fourth paragraph before I ask if there are non-rarepairs for either Rhodey or Sam Wilson.

earlier related discussion