A good number of shade loving plants will tolerate much brighter conditions in winter, typically because the sun is much lower on the horizon and a good bit weaker during this period. I'd consider hellebores for sure and any other spring woodland ephemerals you like or can locate. These tend to be plants that emerge early to take advantage of increased light levels provided by deciduous woodlands to bloom now or early in the season and then they go dormant later in the season.

FWIW, pretty much any shade tolerant evergreen shrub will be perfectly happy in a more sun exposed position in winter as long as it is out of direct wind and receives adequate moisture. It is attempting to grow these types of plants in a year-long exposed position that will get you into trouble :-)

Here is a link that might be useful: spring ephemerals

I think there are some hostas that will tolerate sun and there are some that will tolerate deep shade. Im not entirely sure on the subject but a look in the hosta forum may 'shed some light' on the subject :)

spring flowering bulbs such as crocus daffodils and tulips would do nicely and then die off as your other pernnials came up, providing a sucession of bloom from the beginning of the season and with minimal care