Knit some rainbows as badges, jewellery, bag charms, to hang from mobiles, or to make a rainbow pride banner.
I have added toy filling to make a puffy rainbow, but you could leave your rainbow free of stuffing so it lies flatter if you prefer. If you don't have any toy filling you could use cotton wool balls to stuff it.
The rainbow is knitted in one piece and worked flat (back and forth) on a pair of straight knitting needles. You will need to cast on and off, knit, purl, work decreases, and sew seams.