One of the types of yarn I enjoyed using was the Red Heart reflective yarn. Here is an example of my using it as a contrasting band in a hat.
I've also used it in entire hats, as well as to make high-visibility wrist bands.
Unfortunately, none of the local yarn stores carry it anymore, and while I can buy it online, I really prefer not to, if possible.
Instead, my darling husband found an alternative for me.