I dunno, LGR on youtube seems to find a lot of cool retro tech there[1]. A lot of crap too though. Not American, so I can't comment personally.
1: https://www.youtube.com/playlist?list=PLbBZM9aUMsjEM76RFMofB...
1: https://www.youtube.com/playlist?list=PLbBZM9aUMsjEM76RFMofB...
I'm lucky to live in Japan where we have a junk store called "hard off" that focuses on hardware. They always have some obscure interesting stuff, tons of Laserdisc players, VHD, HD-VHS, Famicom floppy drives, etc. https://www.flickr.com/photos/kalleboo/albums/72157719132609...
In general, vintage stores in Japan are amazing. I don't know how they manage to find such a huge quantity of like-new stuff.