Unconventional Courtship generator plugs fandom character names into 100's of romance novel summaries. It's a great plot bunny farm. You can make your own custom character version, or you can use the one I made for MCU.
Unconventional Courtship Generator, MCU Avengers version has my custom MCU Avengers as an option. Click on it & you'll have the random pairings chosen from Tony, Steve, Bruce, Pepper, Natasha, Thor, Clint, Jarvis, Fury, Rhodey, and Bucky. (Edwin Jarvis isn't strictly speaking MCU, but I wanted him in there.) To make purely Stony pairings put Tony Stark and Steve Rogers in the text boxes.
*sample result* 346) The Real Rio L’Aquila - Sandra Marton
Italian by birth, this street urchin lived a life of extreme poverty until he escaped to Brazil - where he cast off his roots, took a new name, and pulled himself up from the streets.
Now Tony Stark is beyond wealthy, with a reputation for being uncompromising in business . . . and incomparable in bed! But on meeting vulnerable Steve Rogers he feels something deep within him stir, and he finds himself pretending to be that long-forgotten man.
Passion flares and their affair spirals, but Steve still doesn't know that his lover has lied to him. Who is the real Tony Stark?