Most of the small foreground plants need good light. It is a bad time of the year for buying plants as most are grown emersed and don't do well at this time of year. Some that might be available would be: Glossostigma elatinoides; Echinodorus tenellus tenellus, tenellus latifolius,tenellus parvula, quadricostatus, horizontalis, parviflorus "tropica", schluteri leopard; Sagittaria microfolia (does not grow much taller than 50mm). There was also a shorter variety of hairgrass ( Eleocharis) but I have not seen it in years; Cryptocoryne nevilii nevilii; Hydrocotyle verticillata. I have some of the above but not available for sale at this time of year.