They will eat almost anything when food is scarce. However, some plants are less palatable to them. Prickly things like holly, berberis, mahonia, eryngium etc are usually left alone. Hellebores are usually OK, as are foxgloves and sedums. Potatoes and rhubarb are good in the veg garden, although they do tend to dig up the potatoes. They are pests!

But they are cute!

Seem to remember there is a website that lists rabbit proof plants - have a look.