Might be suckers of a shrub or a tree.

The only tree in my yard is a maple. The closest shrub is forsythia, about 20 feet.

Could it be witch hazel or beech?

The coloration (interveinal chlorosis: yellowing between the veins, while the veins show more green) indicates a nutrient problem -- most likely inadequate iron? -- rather than the plant's normal appearance.

I figured that, but it's not something I planted so I don't know if I even want to keep it.

Tree seedling, if not suckers. Hawthorn or crabapple perhaps. Regardless, seedlings coming up in rocks are unlikely to be something you'd want.

I wasn't suggesting you fertilize, merely pointing out that most whatever-it-is probably aren't that color. 8-)

I found this not far from those, it looks similar to those. Time to get the shovel out lol. My neighbor across the street has a mulberry tree, some of the leaves look similar, some don't.

{{!gwi}}

mulberry leaves are variable.. even on one plant ...

ken