I agree about the second one being ajuga. I have several in my yard, and they are pretty common perennials/groundcovers, though mine have darker "chocolate" leaves -- it comes in several shades. I don't recognize the first one as any perrenial or flowering plant that I know, and it looks like a bush seedling or sapling to me, saltcedar's idea sounds likely.

Chenopodium album, as Chris says, Lamb's Quarters WW

Oh boy!! Well, at this point I'm concentrating mainly on getting the garlic mustard out and only pulling others when they're right in with the GM. Hopefully the 2nd isn't as prolific as the GM, or I'll be in another world of hurt next year! I'm still dealing with the remnants of Jerusalem artichoke as well! Yeesh! OH BTW - could #1 maybe be an Actaea? I'm really hoping not to have to pull it - I've got a bit of it in there and it's actually kind of pretty in a group - I'm gonna keep an eye on it, and see if it blooms and what they look like.

Jay, I planted a very small tree there a couple years ago, but I think it was eaten and I didn't think it survived. I will let these live and keep an eye on them.