Creeping thyme is quite nice Stays soft and low Not as aggressive as mint though, so you might have to make space vs just letting the mint go

Of the rest of herbs I grow (basil, rosemary, parsley, cilantro, chives/winter onions, oregano) the oregano isn't too woody or tall. It gets a bit leggy, though it could just be fallen over and accepting of is new life. Also a lot oregano varieties to work with. Nice hot oregano

Unclear how it would directly complete with other plants.