Barley rings and pea flakes are also favourites here. Any 100% dried fruit (I make my own). Hay cookies, oat treats, forage mixes, dandelion root, apple sticks, fresh willow (leaves and the stick - my bun only eats the fresh stuff), dried veggies.
I make most of these myself, but still, somehow spend a small fortune on rabbit treats. Etsy and Instagram are my two go-to's for rabbit snacks - just be sure to check the ingredients