I'm assuming that you are about zone 5.
There are a ton of good shade plants you can go with. It depends on if you want trees, shrubs, perrennials, or annuals. I'm gonna give you mostly shrubs and perrennials for the list, and a good link that you can do some further investigating for your zone.
Shrubs:
Azaleas (all varieties)
Rhododendrons (all varieties)
Kerria (japanese rose)
Acuba (may get too cold, but worth a try)
Perrennials:
Periwinkle (vinca minor) *not the annual bedding plant*
Ostrich fern
Robust male fern
Hostas (all varieties, and there are a lot of them)
Japanese tassel fern
American Maidenhair fern
Liriope (all varieties)
Frosty curls sedge (carex)
A few good trees would be:
Dogwood
Redbud
Japanese maple.
Those are just a few suggestions. See the link below and stop by your local garden center, they will know way more than I.
Good Luck.