It's been a looooong time since I posted recs. I'm a little hesitant to do so. But In my last post, I talked about why I like reading MCU Steve/Tony, and a couple people asked for my recs list. So here's a stab at that. Caveat: sometimes I like Steve/Tony stories for other reasons than the pairing. I don't want to say the pairing is incidental, because it isn't, but I love Tony's bots, and friendships among the team, etc, and so certain stories hit that for me in a big way.
The gold standard for me, and the fic that sets the bar for the pairing, is
As Sharp As Any Thorn by RurouniHime. 42,000 excellently paced words about the cost of arrogance, and what happens when Tony's tech goes awry, and how much Steve and Tony love each other.
Here's some others from my bookmarks (which are all private, sorry). I didn't start bookmarking this pairing until I'd been reading it about a year. But I have about 150 Steve/Tony stories bookmarked, and these are the ones I was moved to write notes about when I bookmarked them, so I'm including the notes verbatim. As always, favorite doesn't mean best, YMMV, etc.
The Act of Creation Will Be Your Salvation by scifigrl47 - Tony and his bots and a (very) slowly unfolding Steve/Tony romance. Verrry sloooowwwwly.
Best Kept Secret by AlchemyAlice. Tony and Nat's friendship is STELLAR in this.
Let's (Slowly Let This Go)by aphesis - shorter, and post-CW. Excellent Tony in this story.
Not About Superheroes (A Private Little War) by AnnaFugazzi - 146,000+ words, the one where Steve comes to terms with being gay and loving Tony
Bring Him Home by seventymilestobabylon - excellent
The Better Part of What I Never Had by lyra_wing - loved this one
Christmas Holiday by scifigrl47 - awesome
Selfless by Silverlace Vine - more like this one please
You Gamble On Everything, All Except Me by Annie D - hot sex and true to character
For The Wheel's Still In Spin by Arukou - nice slow burn. (57,000+ words)
After All of the Sparks (You're Still Alone in the Dark) by bewaretheides15 - pron with protective Steve, v. nice
Run Program: DUM-E by Amuly - THIS STORY IS ADORABLE I LOVE DUM-E
gonna be trouble by fictionalcandie - that one where Steve and Bucky don't climb all over each other the minute Bucky's found
many names in history, none of them are ours by aubkae - this story is so so good, really excellent
Better Halves by kiyaar - loved this one
Rom-Commed by Fate (or JARVIS) by leashy_bebes - that one where Jarvis gets involved
Homefront by copperbadge - why do I keep coming back to this story? it's a mystery. should rec