In the 20G:
some random floating things - duckweed??
water sprite or wysteria - not sure but it has grown alot recently
somethng german sounding - seaweed like thing
I had some others but they went all gooey
The foxtails, dwarf lilly and water sprite thing do the best. Amazon sword and anubias also do well. The bacopa carolina - i find it floating every day. I think my snails knock it out of the sand
I want something to carpet the bottom...but i need something that is easy and not a high light plant