A rock border suggests shorter plants to me, so a mentioning lilacs threw me off. Can you say more about the size of the space and what your goals are in putting in plants?

daylilies and hardy phlox come to mind along with monardas. Raspberries, gooseberries, currents, etc all have thorns and/or prickles than are quite deer resistant. If you have enough drainage for ornamental alliums, deer normally leave them alone, too.

Generally, the deer don't like plants with fuzzy leaves. Try the salvias and veronicas, hens and chicks. There are some excellent list of deer resistant plant online, too

I planted day lilies and the deer mow them down before they get through the ground in the spring.