Flowering annuals are nice and easy. Here's a quick list. Begonia, Impatiens, Torenia, Fuchsia.
Perennials like Hosta and Azalea can't miss.
For greenery in the shade, try Ferns, Pachysandria and Vinca.
You can also move out your houseplants into the shade for the growing season ~ just remember to bring then back inside before frost.