Welcome back and I too had the shade and roots of silver maples until we took one down. But I still have a lot of shade under a large apple tree and here's what I have under it, mostly wintersown:
Pink and white bleeding hearts (Dicentra)
Fernleaf bleeding hearts
Hostas (some WS some purchased)
Ladies Mantle
Jacob's Ladder
Toad Lily
Primula's (a few varieties)
Astilbe
Heuchera
a few cranesbill geraniums
Virginia bluebells
Bergenia
Daylilies
I also plant tulips in between to flower before the trees
leaf out.
Hope this helps for your zone.

Thank you so much. Hopefully I'll be able to round up some seeds for some of these and make my yard a real show stopper in time. I appreciate your help. Hope you have a wonderful Sunday.

I've just discovered Persicaria as a ground cover and filler. It WS'd easily. Another easy one is columbine. I'd start hunting for fresh seed NOW and either summer sow it now or fall sow it. The fresher the seed, the better the germination. Coleus are not perennial, but can offer some color when you can't depend on blooms. Pulmonaria have interesting leaves and beautiful spring blooms and I hear they will reseed and spread, but not aggressively. Good luck.

Martha

Silver maples are thugs themselves and are not aloud to be newly planted in my city. Jacob's ladder is one of my favorite winter sown shade/sun plants and is so easy to do!
Remember the Newbie Seed Project this fall for a large selection of free seeds this winter!