For Steve/Bucky (and often Steve/Bucky/Sam in various combinations) my first rec would be Dira Sudis (http://archiveofourown.org/users/dsudis/pseuds/Dira%20Sudis) Some of their stuff is dark (some very dark and I haven't read due to the warnings) but there's lovely h/c too if you're prepared to go through the characters working through it.