What are some easy-to-make project land forms?

I'm doing a project for my World Geography cl where I have to make at least 30 land forms. So far I have a mountain, volcano, mesa, e, swamp, desert, cave, cavern, canyon, canyon river valley, island, plateau, marsh, valley, glacier, cliff, archipelago, cape, and prairie. Anymore that I can make out of things around my house? Also, is a river a land form? I think it is, not sure.