Cars & Boat Glitter
The glitters aka "Metal Flake" shown below are ones that are OK for use with most standard clearcoats. They can handle solvents, are coated for UV resistance, and can be sprayed. Be sure to use high-quality clearcoats that are actually clear to the bottom of the can. If you use old or cheap brands that say "clear" but are actually not, the color (however slight) can change the look of the glitter. These are PET flakes which have become the new "Metal Flake".