Some ivies. Some cottonwoods (sort of). Aspen.

Redbud, I think it's cercis canadensis and I have long wondered if the canadensis does not mean it comes from Canada but is a term for the color of the early opening leaves?
There is a potato vine that has heart shaped leaves.

Some violets.

Not to be too obvious, what about Bleeding Hearts?
(Dicentra spectabilis)

How about Brunnera?

little-leaf linden (Tilia cordata) tree is another one.

I'm probably too late, but EPIMEDIUM! EPIMEDIUM! The leaves are often rimmed with red!
C.L.