For my area, basswood leaves are huge and more crinkled than linden.
Linden trees often have hundreds of seedlings underneath them. I've
never looked under basswood. I've pulled up a few linden sprouts and
transplanted them. They seem to be doing well, keeping my fingers
crossed that they'll survive winter.

If there's one you like in particular, consider taking a cutting in
spring and root it with some rooting hormones.