Are you looking for something to come back year after year or are you looking for annuals?

Some good annuals are:
Impatience
Begonias
Coleus
Caladiums

Some good perrenials are:
Hosta
Hydranga
Astilbe
Bleeding Heart

I've read that Daylillies will tolerate shade but the ones I have in shady areas don't bloom as well as the ones in full sun.