I pot them up and see what they do. Consider them free Japanese maples.
You can water them where they're at this summer and then put them in pots in late winter or early spring. Then grow them up to see what they do as far as fall color, growth rate, new growth color, seed color, etc.
Mike

Here's a few that survived the culling process.
Mike

Thank you, Mike. If anything miraculous should happen, you will be the first to know.

Depends on how many trees you want/need?

With seedling grown maples you want as many as possible so you can choose the best. Many have nothing special to offer. I like them all, but I'm getting pretty picky in my old age.
Mike

Friend pots them up and sells at her yard sale. Only asks a couple of dollars, but sells them all by end of sale.