sweetwoodruff isn't native, but its a well behaved invasive-- it rips out easily and looks nice. wild ginger can be native or non-native and can be invasive if it likes where it lives. virginia creeper is native and will take over if you let it. nice fall color, nice leaf, has berries that birds like. if you cut it back every few years it stays manageable

diggerb

I second the sweet woodruff - it is indeed "well behaved". Lily-of-the-valley. Goutweed is very invasive but pretty.

Creeping foamflower (Tiarella) will cover the ground quickly when happy.

Hardy begonias will shade out anything and have pretty pink flowers in summer. I have them in almost full shade, and they even shade out the quack grass which is rampant in most of the garden.

I also second Begonia grandis as very desirable. However, the deer in my area also find it desirable so they tend to destroy areas of it on a random basis. Luckily, the new babies each season keep it fairly common in my shade areas.

George

I use "camoflage plant" in my shade garden--in the sun, it would be horribly invasive, but in the shade it's manageable and provides nice color contrasts depending on where it's established itself (totally green in full shade, tinged with cream in dappled shade, and with red where it gets more sun. I've found it to be a great "filler" and is easy to pull up, which you will have to do. Is about a foot tall, gets insignificant, but cute white bloom. It does have a interesting scent of citrus when you pull it up.