Plants that we find beneficial for keeping goldfish are those that are hardy, supply nutrients to the fish and use a lot of nitrate.
Favourites are the floating plants: frogbit and azolla
Helpful plants that goldfish will eat, but recover quite quickly: elodea,  hydrilla
Plants that goldfish will nibble but don't eat much at all:
hornwort, anubias, vallllisneria nana
Picture
Vallisneria nana

Plants we don't like in our tanks:  java moss (hard to gravel vacuum) and duckweed (goldfish don't like it very much and it needs to be contained or it can grow out of control).  Duckweed is still a good standby to help take up nitrates out of the water however, so we do keep some duckweed in our tanks but we keep it 'under control' by harvesting it if the goldfish don't consume it quickly enough.  Azolla is much easier to control as the goldfish love to eat it.