Happy Highways Where I Went by perclexed - crossover with the British murder mystery series Lewis, with the premise that the titular detective is a distant cousin of the MCU's Darcy Lewis. There are actiony bits, but mostly it's about the characters from each canon getting to know each other, and it's charming. It does a good enough job of introducing the characters from Lewis that it worked for me without ever having seen an episode.

Dreams to Sell by Prochytes - crossover between Agents of SHIELD and Torchwood, with Gwen Cooper from Torchwood reluctantly teaming up with the SHIELD crew to deal with somebody trying to steal a dangerous ancient artifact. This one, I'm not sure how well it works if you're not already familiar with both fandoms; it uses some quite specific plot points, but I knew them already so I can't judge how well it would work for someone who didn't.

And, finally, an untitled Tumblr ficlet on the subject of "If Sesame Street exists in the MCU, how did they deal with the Snap?"