If you want glow in the dark markers, check out Amazon (luminescent tape). There are many sizes, shapes, rolls, dots etc (search showed 158 results) in sticky back form.

Stick on both sides of piece of plastic if you need to tie it to something. Otherwise just chop off a chunk and stick it to whatever you want to mark.

Use different shapes or clusters to identify items by groups. Triangle means one thing, square another.

Been using this technique for years. Learned it in the Air Force.

Nomad.