Hi Debsma and welcome to GoY. Scroll to the bottom of the page go to 'S' then look for shade plants, you'll find lots of info on shade and moisture loving plants.

Astilbe, ajuga reptans, Mahonia aquifolium, geraniums, lamium maculatum varieties, hostas, heucheras (though not if its wet all the time) Fatsia japonica, Lysimachia, convallaria, primula/primrose/polyanthus, ferns are a few. If its really wet all the time, click on B at the bottom of the page and look at bog garden plants.

Not forgetting tricyrtis....

..and Hydrangeas for later colour. It depends on how deep the shade is and whether it gets any sun at all during the day or is over-shadowed by trees or buildings. Areas with some sun or dappled shade have more potential than , say, a north facing wall.

..............don't overlook ferns, I've a very shady and moist corner that I've turned into a fernery, easy to look after and easy to propagate too .......................

. . . and Epimediums, Pulmonarias and Camassia.