If you are goign to do it, I would suggest Anubias- they are as bold as the goldfish.
research up on the varieties- they can handle low light, high nutrients and generally easy care IMO. First and foremost, goldfish produce huge amounts of waste, therefore I would not recommend anything substrate planted if you are looking for easy care (gravel).
Anubias would be attached to wood or rock, which could be removed during cleaning, etc. Very easy, and you can do some pretty amazing things with it.
Test water perimeters often, if needed, frequent water changes