It's funny, I was just looking for new fics in this tag last week! I've read dozens with this duo, and honestly, my favorites tend to be the ones where Eri's role is a bit more active, not just as a cute accessory for Izuku. There's this one called 'Rewind, Reset' where a temporal quirk accident binds their timelines together—every time Izuku gets injured, Eri accidentally rewinds him, but it costs her lifespan. It's devastatingly angsty, but the author handles the found family dynamic with so much care, and the ending made me cry in a good way.
Another top-tier one is 'Aftershock'. It's a post-war AU where Izuku has taken over managing the agency and unofficially adopts Eri while she's struggling to control her quirk. The slow-burn on Eri coming out of her shell feels earned, and the scenes where she tries to bake him terrible cookies to cheer him up after a bad day just melt my heart. Some people find the pacing a bit slow, but I think it builds a solid foundation for their relationship.
I'd steer clear of the super fluffy, tooth-rotting stuff unless that's your specific craving. The deeper fics where they actually help each other heal from trauma just hit different.