Food sells well, given that the Coliseum drops a lot of it! I have two pages of stacks of food, and stacks of food can sell for five figures. I Coliseum-farm just for the entertainment of watching what drops, and for familiars--I am a familiar collector but I am too stingy to buy them--but I sell off stacks of food now and then when I judge I'm not hurting for any particular kind.