Vallisneria sp. ‘Natans’ from Asia is a hardy plant for beginners. It has fine, narrow leaves (50-100 cm long, 1 cm wide) so it does not overshadow other plants much. Easy to propagate using its many runners. 
A bundle of stems or young plants gathered in an anchor. Remove the anchor and split into separate plants. Regarding stem plants, remove the leaves from the lowest 5 cm (2“). Remove any damaged leaves. Plant the individual plants with some distance into the bottom substrate. Roots will develop soon and the plant start growing.