Have you looked at the cultural requirements for Aucuba japonica?

I have my varigated Hydrangeas in deep shade (north wall and tree cover) and they happily lighted up the corner.

Witch Hazel - generally a carolinian understory shrub with a unique appearance. We have one in the sun and one in the shade under sugar maples and the one in the shade does best. In the shade the leaves are medium green to a chartreuse green and in fall the leaves turn bright yellow. It also flowers in the fall with very odd looking yellow flowers and when the seeds ripen the shrub "spits" the seeds from the flowers. Here's a site to show you the features:

Witch Hazel Shrub

Barb

Cornus alba 'Elegantissima'
Variegated redtwig dogwood. It is dazzling in shade.

Here is a link that might be useful: Cornus alba 'Elegantissima'

Annabelle hydrangea is a standout for a shade garden. Tough as nails, it can be pruned severely to maintain almost any size and has huge white flower heads which turn tan in fall and can be left on for winter interest. Rabbits/insects/deer don't seem to care for it. My plants get no direct sun, very little light, and still do great year after year.

Kate

I thought we'd had this thread a while back, and I thought I suggested Sambucus nigra 'Variegata." Or was that on another forum?

I second the recommendation for the cornus alba "Elegantissima"! I had one in Canada...it was gorgeous. It grows like crazy when watered, so if you wish to contain its size, underwatering is recommended. The red stems in winter against my white house were beautiful, and birds liked it for summer refuge from the local predators.

Good luck!

Here is a page for the best full shade shrub (bush):

http://www.missouriscenicrivers.com/shade-shrubs.html

Here is a link that might be useful: Best Full Shade Shrub (Bush)

I have 3 female Skimmia Japonicas in a contained area on the north side of my house near my front door. They literally never get any sun but the area is 'bright', not dark and murky. They are very healthy and produce many red berries. (The 'boys' are around the corner about 20 feet away in another sunless spot, and they do well too.) The shrubs are about 8 years old now. (Silverdale, WA)

Here in Maryland, I can't plant red twig dogwood because the DEER eat it. Same for redbud, which would have been an alternative. I do have Nandina doing well in part shade, as well as skimmia and cherry laurel Otto Luyken. Ferns are always appropriate. Hydrangea is nice, but I'm not sure about really dense shade. There are variegated hydrangeas which would look nice there. How about viburnum? I have several, and the deer don't bother them.

Florrie

So floorie2 or someone else - the deer don't eat your Otto Luyken? That would be great news, since I'm in a similar situation to the OP, but with the addition of a deer problem. TIA...

I think the variegated red twig dogwood sounds good. You get the added red twig winter interest. How about variegated Kerria Japonica? You get flowers, variegated foliage, and green winter twigs. Mine is flowering right now and is in shade under maple trees.

How about Itea 'Little Henry' - Virginia Sweetspire I think is the common name.

^^ Funny that you mentioned that one. I have the 'Longspire' variety of Itea right next to the Kerria. I just have to make sure the Itea does not dry out since it like it fairly moist. Great for fall color.

Since this post is 2 1/2 years old, I know this isn't helping the OP, but I found it through a search & I guess others are doing the same. I'd suggest Osmanthus 'Goshiki' to beautifully brighten shade.