Polyanthus Primrose, Impatiens (when it gets warmer), Begonias (ditto), Wishbone Flower (Torenia, again, ditto),

The brightest will be begonias and impatiens and both will tolerate or even prefer shade. Have you thought of a pot or two of ferns on the patio as well?

Hanging baskets in shade do much better than those in full sun usually because they don't dry out so much. Use fuchsias, lobelia, begonias, busy lizzies and pansies - all of these tolerate shade really well. Wouldn't recommend helichrysum or its grey leaved like for contrast though, they like full sun, so if you want a non flowering contrast trailer, use small leaved ivy.

Or variegated Vinca major, or Lamium.... : )