I see you are in the US, so it could be local legislation related.
Normally rear reflectors are incorporated into the rear lamps, but if not, the additional ones are usually larger than those tiny ones you have.
The square holes suggest factory fitted. So, I'm coming back to local legislation demanding them.
I'd be surprised if you ever find another, so you may need to source something from a cycle/motorcycle shop, and find a pair that look acceptable.