I have a guncon3 somewhere around. It works with a pair of sensors placed on top of the TV, like in the PS Eye and XBox Move era. No CRT was required for that.
The length of the cable between the sensors was made for something like a 40" screen though, so if you play on a larger screen they sit a bit toward the center instead of in the corners where they are supposed to be.
I went to a gamestop a few months ago to see if they had any games for my Gameboy Advance. The dude at the register said I might have better luck at the “retro game” store in the next town over. I nearly spit out my Crystal Pepsi at him.