I can't find three Steve-centered things that I'm sure were on tumblr, which is a nightmare to try and search.

1) An old historical facts type post, about how the ring-pull tabs on fizzy drink cans were invented during the time Steve was in the ice. It was illustrated with a chibi of Steve squinting suspiciously at a can/ring pull.

2) A short fic set after the Avengers- Steve has just moved to DC, and decides (or maybe is nudged by Natasha?) that he's not going to repeat his sadness errands from between CAtFA and TA. He starts by braving a shopping mall to get new trainers, although initially he asks for something practical/hardwearing/resilient and gets offered something like crocs before going through the process of being measured & fitted for proper running shoes. The ficlet ended after he's got the shoes, on his first morning run around the National Monument when he sees another guy out running, segueing into the meeting with Sam at the beginning of the Winter Soldier.

3) I thought this might be an Imagine Steve post, although I can't find it on their blog. It was a prompt or headcanon 'what-if'; about how what would happen if the Serum functioned so that Steve could revert back to his pre-Serum state mostly at will, but it would happen involuntarily if he was particularly stressed or worn out. With all the stress post-WS of the fall of Shield & trying to find Bucky, he reverts back and that's when Natasha comes over to see him and finds out. I'm not sure if it ended on a suggestion of using him in his smaller form to try and lure Bucky out.