"Hi-Viz emergency vehicle safety" stickers. For use on helmets, vehicles, object markers, things you want to be seen in low-light conditions. I believe 3M already makes a Hi-Viz reflective material you could then print custom designs on.

I know there's holographic stickers, but that's more of a "rainbow rare Pokemon card" situation

I need stickers that are reflective and can be seen in day time and at night.

I own a construction business, and we need reflective hard hat stickers and also reflective numbers.

Please add Chrome Vinyl stickers! Print designs on a shiny Chrome vinyl. Add under printing of White for opaque colours, or print normal translucent inks to allow a coloured foil look.