This is a little tip that I saw recently on a crafting channel and thought was such a great idea that I would have a go and try it.
Glue gun big dollops of hot glue on a silicone or glass sheet and immediately sprinkle with glitter of choice. Wait a few minutes to dry completely and then peel off and use.
This was my first attempt so they are a bit misshapen but have done some more and they are great. Can coordinate the glitter to match whatever project and cost a fraction of the cost of buying them. Can make approx 50 large ones from a single glue stick