Bonk! offers some clever aftermarket stickers more in-line with cyclists needs. I’ve seen reflective 3M stuff sold previously, but it’s generally in awkward shapes and sizes. The nice part, is that the color options offered actually allow your reflective coating to blend in to the bike. This picture doesn’t do a good job of capturing the effect, but the fork has a line of black reflective tape on the trailing edge. I want my pretty new rain bike to still look good after adding some reflective material. I’m not big on the yellow and orange triangles.
UPDATE: Here’s a good example from the Bonk! site showing the Day and Night behavior of the reflective strips: