Hi!
Cryptocoryne grow well in low light. Also Bucephalandra, that is more medium.
You may also use Hydrocotyle tripartita (keeping it a time in vertical position, then after on the ground; it's easy to handle this way).
Legenandra meelboldii Red is OK if is not in shadow of other plants. Same with Alternathera Red and Pogostemon Helferi.
All these plant grows well in my small tanks as wel as in 100 litters tank.
But, although all are plant with low to medium light requirements, need a good/complex fertilization.
We should take always into consideration light together with fertilization.
I gues you know already this ...
Good luck!