In aquariums, aquatic epiphytes (java fern, anubias etc) grow without dirt. When I first started vivariums, I was surprised by how many terrestrial epiphytes there are. Plus most aquatic epiphytes can also be grown terrestrially. I have java fern, christmas moss, anubias and bromiliads growing on wood in my vivarium. I'm sure there are lots more options, but those are the ones I have tried.