Beautiful pictures. Here's some help on your unknowns....

#5 looks like jack-in-the-pulpit
#15 looks like another fern
#16 meadow rue
#23 baneberry, Actaea sp.

FataMorgana

Thanks for the ID's! Yup, JITP would make sense, I have a ton of them and propagated dozens more from seed last year. They always seem to come up later. The list of what I found last year is:
Erythronium albidum (White Trout Lily)
Trillium grandiflorum (Large-flowered Trillium)
Uvularia grandiflora (Large-flowered Bellwort)
Arisaema triphyllum (Jack-in-the-Pulpit)
Podophyllum peltatum (Mayapple)
Sanguinaria canadensis (Bloodroot single and double-petal)
Viola sororia (Common Blue Violet)
Viola pubescens (Downy Yellow Violet)
Wild Ginger
Salomon's Seal
Interrupting Fern
Ostrich Fern
Elderberry
Chokecherry
Fruiting Mulberry
Star Magnolia
Virginia Waterleaf
Virginia Creeper
Caulophyllum thalictroides (Blue cohosh)

I also planted some seeds this winter.
Dicentra cucullaria (Dutchman's Breeches)
Penstemon digitalis (Foxglove Beardtongue)
Monarda bradburiana (Bradbury's Monarda)

And last fall I planted the following seedlings:
Stylophorum diphyllum (Celandine Poppy, Wood Poppy)
Anemone sylvestris (Snowdrop Anemone)
Campanula (Blue Clip, Bellflower, Harebell)
Anemone vitifolia (Anemone 'Robustissima')
Tricyrtis hirta (Toad Lilies)

There were originally yellow ladyslipper's that I am keeping an eye out for. The original owner who started the woods had a bunch but gave them away when he moved as he didn't believe the new owner would care for the woods. He was correct. I've been busy removing garlic mustard, creeping charlie and buckthorn as well as debris. It could have been worse though.

Beautiful photos. I love to see great examples of our lovely natives, but I also love star magnolia and many other non-native plants.

You are so fortunate to have so many of the double bloodroot. I have only a few and no clue where they came from. This year I missed the bloom...was out of town..and a storm took the petals away. As all gardeners say, just wait until next year!

Thanks for sharing your bounty.

Thanks.I actually only have about four of the double bloodroots. I marked where they are and will divide them this fall to get some more. I have a lot more of the single. Such a beautiful flower, too bad they are so shirt lived.

Very nice pictures! Thanks for posting. I enjoyed them. :)

#16 looks like columbine to me.

#16 - Columbine does look similar, but I'm positive it is meadow rue. See the images linked in below.

FataMorgana

Here is a link that might be useful: Google Images - Thalictrum dioicum

Beautiful photos. Yes, #16 looks just like my Thalictrum dioicum, got a couple plants started from seed and I think they're going to bloom for the first time this year!