Although we originally had a few buttercups in the moist areas along our creek, browsing by deer eliminated them, and we have had to reintroduce them. With protection they are now doing well and a few new plants have arisen.
Anemones offer our first spring flowers, even as early as late January in a warm winter, lasting as late as April. They seem completely deer resistant.
From a limited initial population larkspurs have increased in number and distribution over the years. Deer browsing has been relatively light, but if larkspur grows adjacent to a plant the deer desires (such as gay feather), its bloom/buds are likely to be eaten along with its neighbor.
Larkspur is easy to grow from seed and frequently volunteers in containers where I have not planted it.