Well, 'Unlikely Allies' is a stony love - hate fanfic that you might like. It starts with Steve and Tony hating each other's guts due to their different ideologies. But as the story progresses, they start to see the good in each other and fall in love. 'Opposites Attract' is also a good one. It plays on the classic love - hate trope, where their arguments are filled with sexual tension. There's also 'Love in the Midst of War' which shows how their relationship evolves during a battle - filled scenario.