I found that Pygmy Chain Sword, Echinodorus Tenellus is the best plant for a low tech tank without CO2, and without soil, just holland sand. Annubia, Java Fern, Java Moss all will melt in my tank after a few months, but this plant just keep growing. Other excellent plant for non CO2 tank are those long hair grass. Dwarf hair grass will grow too, but algae tend to grow on them.
Remove lots of other plants in my tank to make space for Echinodorus Tenellus to spread.
Side view of tank
Even closer view, You can see the hair grass too.