Where are you located geographically? Round here Hartstongue carpets woodland floors but it needs the right clmate.

I am in Connecticut. Zone 6.

Hay scented fern is the native groundcover of a lot of the Poconos. I have wild cinnamon fern growing on the edge of the swamp, which may work if the slope is moist.

Here is the native range of Hart’s tongue ferns in the U S. https://www.fs.fed.us/wildflowers/plant-of-the-week/asplenium_scolopendrium_americanum.shtml

Hmm, maybe I should try and find some Hart's tongue. It sounds like something that might do well here.

I'm partial to autumn fern (Dryopteris) -- especially since it can take soil on the drier side and tends to stick around longer in the fall/early winter. I would stay away from Ostrich fern -- too windy and they look like cr*p. Plus, they won't give you a carpet-like effect.

New York fern is similar to hay scented and would probably work too. Thelypteris noveboracensis

Ostrich ferns are good fast growers.

Both in my previous home and my current one I have an area carpeted with hay scented fern. It is lovely and seems unfussy as long as it isn’t super dry. Two possible drawbacks would be its ability to spread wherever it’s happy (which is also a plus) so don’t expect it to stop without a barrier, and it isn’t evergreen and so will completely die back in winter. I typically have the area mulched so it just looks neutral and is less likely to start weeds when the ferns have died back. Mine are self planted colonies.