Car's, houses, boats, etc. A house, for example, is perfectly legal to own of course. But if you are caught growing pot there, the house can be seized. I read an article a while back, a young man was living with his grandmother in her house. He was busted for drugs, a few pot plants were found hidden in the backyard (by the grandson, unknown to the grandmother), and they still seized the house. But they were nice, they let the grandmother stay until she dies.
edit: large amounts of money with no proof where you got it can many times be assumed drug money and seized as well