The first photo is Ligularia. It is a perennial. Someone purchased it. 

The second image is a trout lily leaf (Erythronium). It is a native plant in the lily family. I think it is a desirable plant. I would love to have them in my yard! Here is more information about them from the UM herbarium with photos. 

The third photo is a common garden weed, commonly called cursed buttercup (Ranunculus sceleratus). It is toxic to humans and animals. Wear cloves and long sleeves when you remove it (it is a skin irritant, but poisonous if eaten). It spreads by seed, so you want to pull it as soon as possible and dispose of it in lawn bags picked up by the city. 

All three of these plants thrive in wet environments. If you are planning a garden, make sure that you choose plants that can tolerate poor drainage/lots of water. 

Thank you so much!!!  

The trout lily leaf is popping up all over the place in a shady area that had become overgrown and that I am now trying to clear up as a shade garden.  I wish there was an easy way to get some to you.

The cursed buttercup was growing out by our pond.  I originally thought it might be some columbine that had grown from seed from my garden.   I'm glad that I checked with you and appreciate your cautions.

And the third plant was given to me by a friend.  Unfortunately, we didn't know what it was.  I have the perfect spot for it.

Thanks again and have a great weekend!

Happy to help! Happy gardening!