Could change up from hearts to Christmas trees, or Christmas star and such. Valentine bookmark craft kit from Kazsmom on Etsy. Looks like hearts laminated between two lamination sheets to me, with hole punched in the top for a ribbon.
Origami is a little tricky for them because they don't have the dexterity, but with a little help they made origami bookmarks and christmas trees as an activity. They had fun with it. Folded Paper Heart Book Page Marker – DIY