Have a look at Long Acre Plants website.All they sell is plants for shade so there are heaps of good ideas there.
They also have a wide selection of evergreen and deciduous ferns in case you want more. Makes a difference if its dry or moist shade too, and dense or light shade..

Things I have are daffodils (can go quite close to deciduous ones) Pulmonarias, Hellebores,some geraniums.Chionodoxa. There's a white Aquilegia, sorry can't remember its name and I haven't tried it yet. And there's Lamprocapnos (bleeding heart) That does OK even shaded by a magnolia. English bluebells if you can control them...and a Saxifrage whose name I forget that's OK under the magnolia as long as it isn't overtaken by total darkness.... There are some beautiful blue anemone nemorosa that go well with ferns.

There's a yellow flowered Epimedium that has fabulous spring foliage but it does spread rather widely.Species gladiolus and Dutch Iris will grow in medium shade - worth a try if they get a bit if sunshine and don't forget Brunnera Jack frost and some more recent ones.

Depending on how shaded it is you might try a fuchsia or two and same applies to Crocosmia though they do prefer sunshine.

That concludes the tour of my shade....

You could add Hostas and Foxgloves to the list. I grow a lot of ferns and have twelve different types.

Hi, there are over 10,000 species of fern, but the major groups are, Adiantum, Asplenium, Athyrium, Davallia, Dryopteris, Nephrolepis, Onoclea, Osmunda, Phyllitis, Platycerium, Polypodium, Polystichum and Pteris, these have varying degrees of shade needs, ferns are usually moved or divided in spring, plants to go into shaded areas, apart from the ones already mentioned, include, any Anemone *,Bergenia, Convallaria, any Aquilegia, Astilbe, Cyclamen*, Heuchera, Hypericum*, Lamium*, Polygonatum, Primula, Tiarella, Tolmeia, Trillium, Trollius, Vinca*, Viola. again these have varying degrees of shade requirements, the species marked with * will withstand dry shade, Derek.

I use Tiarella, bleeding hearts, hostas, periwinkle and brunneras amongst my ferns. In the late winter, I cut back all my ferns (the winter winds destroy them) and then I enjoy the early spring flowers. My ferns don’t get going till June. Then they shade out the other plants, but they don’t seem to mind too much thus far, and come back in spring to have their time.

Heucheras would also supply colour all year round with their foliage

Between my ferns and hosta, I place a variety of potted Begonias about 2ft above ground level to allow them to cascade down. If you are looking for seasonal color they grow wonderfully in the shade.

Just noticed I've got a fern trying to push it's way into my garden. I'm thinking let it overwinter & then move in March next year. It's a welcome addition for my deeper shade.
They're tough as old boot's toughest grandad but the more roots you move the better

Leucothoe is also good in shade. :)

Do you want something exotic looking, mysterious & just amazing? Check out 'Black Magic' Elephant Ear. The black, almost purple leaves will contrast nicely with the ferns. For smaller plants for up front, look at 'Begonia Escargot' 'Begonia Connie Boswell' 'Begonia T-Rex Ruby Slippers'

Goodness me! There I was racking my brains and now I'm spoilt for choice! What an amazing list. I'm going to be really busy now, trying to sort out some of these plants and then tracking them down. Thank you all very much for taking so much trouble. You've been really helpful!