Lovely things, and if I were smart I would put them in a nice old frame, but I do try to keep things simple. Late 19th c. or so,  I believe, and cut of a thin, natural colored paper--perhaps by a kindergarten teacher or perhaps as love tokens of sorts, I am not completely sure. I purchased these from the collection of the late Elizabeth Baird, a lifetime collector of fine ephemera and valentines, and personally view them as in the latter category. I'll include the board they were stored with (the blue and gray and white pictured) in case of use, though I might personally frame all three together. 

First photo shows them all together in accurate proportion to one another. Upper left:4 3/4 x 3 1/8; lower left: 4 13/16” d; right: 6 1/4 x 6. Sold as a set. All in very good condition, not brittle, with one small torn bit on the star at lower left, still attached at one end and I don't think at all detracting.