I've got 3 on my list.
- BT-PAN Access Point - Kinda ridiculous, but I'd like to have one. I've also found a few BT-PAN-enabled dial-up modems, but I'd have no way to connect those up. Some of those could even be connected to USB printers for wireless printing. Not particularly useful anymore, I just find those devices interesting.
- Dot matrix printer - This one isn't even as ridiculous. I really love that sound and how the text they print looks. Sadly, if I am looking for new ones, a basic 9-pin Epson dot matrix is around €200. But the ribbons are cheap as chips. In fact, often even cheaper. Just imagine casually handing out a document printed on dot matrix to someone nowdays.
- Nano pocket drone - Something like FQ777-124. Maybe a toy like that is a bit childish, but it still can be fun. In fact I already tried to order this one. From 4 different sellers, twice on AliExpress, twice on Amazon. I never got it :(
Thermal Camera.
They're just so cool. Super useful for checking the effectiveness of stuff like insulation or heat sinks, and can be used to find hot spots you didn't know existed.
I just have trouble justifying dropping $300 on something I would only get maybe an hour max of usefulness from before it sits in a box for years.
I got to use a thermal cam for research out in the desert for a summer photographing rattlesnake ambush sites, it was awesome.
(From what we could tell the snakes in fact did not use thermal cues for their ambush sites, just their eyes. But I got to play with a thermal cam)
I did this but with an infrared thermometer gun. As far as everyday use goes, it's super helpful for cooking.