Maybe some of the more sun-tolerant hostas. Actually, if it's only a couple of hours of sunlight, probably all but the real sun-haters of the hostas should be okay. Some of mine end up covered with oak leaves every fall and it doesn't seem to bother them, and by the time the leaves come down, the hostas are pretty much done for the season.

My largest hosta garden was designed to collect the falling leaves of autumn. It is under a forest canopy, and I use various flowering plants for contrast with the hosta. Leaves are piled over the garden to a depth of about 3' or more.
Weeding is minimal - less than 2 hours total per year - a light scurf with the hoe in spring, summer and fall. I rarely have to water, and have never fertilized. I wait until the danger of frost is past, then part the leaves and clean them away from the base of the hosta, to eradicate slug habitat. If the leaves look too untidy, I hide them behind the largest plants.
Leaves are a gardener's best friend. I have often wondered why people spend so much money on soil supplements and peat moss when leaves are free and do a better job of conditioning the soil.
Companion plants to hosta in this garden include aruncus, digitalis and brunnera, all of which thrive under this regime.

Hellebores should do well under such conditions and I think aconitums should be able to push p through the leaves. The ferns like ostrich, cinnamon, autumn and Christmas ferns should work.

The main question is how deep the leaves get and do they pack down densely through the winter forming an impenetrable mass? My yard is surrounded by major forest. If I didn't take most of the leaves off, almost nothing would grow up through the yard deep leave cover.

I have a bed that fills with leaves and acorns - a bajillion and all have sprouted, hundreds every week for months. My thoughts were kind of the opposite, that I didn't want anything but naked stems from taller plants at ground level so I can see these sprouts before they get too big to pull. They can come up in the middle of some Dianthus that is there, which is definitely a solid mass. They can also sprout under a rock or potted plant, then just go sideways until they find the edge, so it doesn't seem to me like any kind of ground cover plant would stop them. Just some calories for consideration from me'n'my tree...

I have old-fashioned plain blue Jacob's Ladder (Polemonium reptans) which grows in quite a bit of shade and gets buried in red maple and Halesia tetraptera leaves each fall. Actaea racemosa AKA Cimicifuga racemosa (black cohosh or black bugbane) won't be bothered by leaves IME.

To some degree, the type of leaves matter. I find that oak leaves (pin, northern red, and white) tend to not rot, but pack down in thick masses that are difficult for most plants to grow through. I don't have that issue with other leaf types. Also, IME most maple seeds sprouting are pretty difficult to discourage. I can't think of a plant that would do much to discourage them.

Hello there, thanks for your answers. (Funny, somehow the notification-thingy didn't work, the mails weren't forwarded directly).
So, it shouldn't be Hostas, as there are enough in other areas. Hellebores are not dense enough in my opinion. But I will definitely go for Brunneras.
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The trees are a Tilia (Linden tree) and a Acer pseudoplatanus (Norwegan Maple?), and I think the stuff will break down and rott completely. And I hope that a thick layer of old foliage and perennial leaves will reduce the number of seedling, we will see.
The ferns and Aruncus should help as well .
Well, have a great autumn and a good planting season,

bye, Lin