This will be a regularly updating page, so come back any time! Just a heads up, I primarily know about plants found around northern Appalachia, so be wary about going around eating plants that look similar in, say, Siberia. Also, please don't excert yourself getting to a plant, and only take a third of whatever you're foraging – leave some for others, and you want to make sure that the plants come back next year!
First up, lets talk about one of my favorite plants, Sassafras albidum, or just sassafras. It's a small tree or shrub with three (three!) different leaf shapes, that being eye shaped, mitten shaped, and like those bed sheet ghosts trying to attack you. There'll typically be a combination of all three on a given plant, and that combination is a key identifier. Additionally, when rubbed between your fingers, the leaves will smell sweet and the roots smell like root beer. Color wise, the leaves range from light green for younger, smaller leaves to dark green for larger leaves. The roots used to flavor root beer, hence the name, and leaves can either be made into tea or dried and ground up into filé powder for gumbo. Here's a picture :)
Next up is good ol' Achillea millefolium, or common yarrow. Millefolium means "thousand leaves," a reference to its feathery leaves, and Achillea references Achilles, who supposedly used the leaves to help stop bleeding wounds, which is its main use outside of being pretty. Be warned, yarrow has two main lookalikes, Queen Anne's Lace (Daucus carota) and Poison Hemlock (Conium maculatum). Poison hemlock is highly poisonous, so be warned! Please do further research into them, as I'm prone to forgetting the differences between them as someone who isn't experienced by any means.