This plant likes to grow next to other plants, like my hostas and bushes. Often there will be holes in the leaves.

Are they ash tree seedlings ?

Looks a lot like the ash trees that pop up here all the time
But I am no expert especially from photos
I am better when I can touch and smell the plant

Cross posted
I was typing while XiaoLong gave you the same thought

Thanks, @XiaoLong and @gardengus. It may very well be an Ash tree seedling, but I'm not entirely sure. However, why are there so many of them around my neighborhood?

I'm pretty sure that Ash tree seeds are dispersed by the wind. They can end up pretty far from the parent plant. Sometimes there are seeds in mulch; did you pick up an local (not bagged from the store) bulk mulch? Around here we end up with a zillion Elm seedlings in the local free mulch.

No I didn't, @greene. We don't even have mulch around our house. They also seem to come back every year at the same spot, but this year I notice many more.

Maybe there was a tree in your yard or near years ago , the seeds can be viable for several years .
Some years are just great years for germination for whatever cause.

Perhaps. I have noticed a lot of maple tree seedlings all around my house too. Must catch all of them before they grow into trees.

Ash seeds are dispersed by wind; after that they can be further dispersed by water, animals, etc. No telling how far the seeds can travel.

I have an abundance of locust (the kind with nasty thorns) and mulberry (with 2 foot tap roots ) this year

Yikes! Pulling out those locusts must be hard.