You did not specify moist or dry, or if you have deer problems. That makes a big difference. I made a list from Cullina's book for dry shade, deer resistant, and I have found most of these (during rescues) on slopes: actea, allium, aquilegia (blooms better with some sun), asarums, arisaemas, geraniums, mianthemum canadense, podophyllum, sanguinaria, smilacina, heuchera. Ferns are good if you have some moisture. I especially like the sanguinarias on a slope, although I have to admit something ate the buds off a few plants years ago.

On a rescue, we found a very steep site, which we called bloodroot hill, covered with sanguinarias. It is now under water since they built a dam near there, but we rescued as many as we could...had to leave some, since we were not mountain goats.