Looks like an oak seedling, but just too unfocused to say for sure. But if you're in a cold climate and your tray is outdoors, an oak seedling should have dropped leaves by now.

It looks like a Senecio vulgaris to me that has lost its flock. They are cold weather weeds but will grow - and bloom - any time of the year. It is listed as an obnoxious weed. Too bad it isn't something cool.

This was outdoors in freezing weather so ill assume its Senecio. Thanks!

Yes. That's Groundsel.