Some good foreground plants, not including Glosso:
Ranalisma rostrata -- stays shorter than E. tennellus v "micro," light green color. Grows quickly and forms dense carpets once it gets going.
Marsilea quadrifolia -- "lazy man's glosso" which is a dark, glossy green color. New leaves are a golden color. Can withstand very low light (less than 2 wpg). Tends to shoot out really tall leaves occassionally. Simply snip these off as they show up. For those who don't know, Marsilea is actually a fern.
Lobelia cardinalis 'small form' -- very fast to propagate given intense lighting and lots ntrate+phosphate. Tends to concentrate more energy on producing many sideshoots rather than vertical growth. To propagate, simply snip off these sideshoots and plant. Very unique!
Other choices that Jay didn't list:
Anubias barteri v nana
Sagittaria subulata 'dwarf'
Eleocharis acicularis
Blyxa japonica
Hydrocotyle verticellata
Carlos