If you rummage thru the clearance bins at fabric stores sometimes they have those embroidered patches that you just sew on. Or take some lace fabric and layer pieces with denim.
BTW: I sew weighted blankets for autistic kids and it sounds like you will need some more weight to make it effective. It will depend on how large a blanket it is. I once used patches of jeans with the back pockets still on and sewed the pockets shut with weights in them. I used heavy duty washers but most will use poly beads. Just some info.
