Paper mâché masks are a fun one to do. Works for Mardi Gras and the fancy ball. Paper clay, homemade or other can be used and mâché paper strips work too.
( I made and sold gilded Venetian masks for 10+ years)
If you have any local thrift stores, they might have some ceramic or plastic masks you can use as molds to make masks. A layer of wax on the ceramic ones and you can just pop mâché pieces right off them after a day or 2 of drying. Easy to do a whole bunch so they can have a range. I would do strip mâché over the whole thing and then cut the eyeholes after, to fit each design.
Lace bits, cording, leather scraps, ribbons, beads, leaves, fake or real and any other bits around can be used to decorate them and then paint. Gilding isn't too hard, but it can be a bit pricey to get all the supplies to start.
It's a very old craft too. Lots of history.
