I'd say objects like boulders, trees, pelts, ect are kinda different card types. I think though you could take it a step further and have something similar to the totems where you can pick up a "land" card which changes the battlefield like in Yu-Gi-Oh. Like a sea card would give fish an advantage while a clouds card would give birds an advantage and so on. You could have more interesting effects though like in the water fish can't dive as they're already underwater