Regarding pretty odd things on Amazon (beyond all the normal stuff)...
I've bought a replacement motor capacitor for an A/C condenser fan on one of my HVAC units... Got it faster than I could get an A/C repair guy here to replace it...
A Paraffin Cartridge temperature regulating shower replacement valve and numerous other odd plumbing parts. Didn't need a plumber.
A Hakko Soldering Station FX-951-66. This has replaceable elements for very small soldering iron tips that are temperature regulating and very high power (up to 75 watts). I also got a wide variety of tips to go with it all on Amazon.
A X-Tronic Model 5040-XR3 All In One Hot Air Rework Soldering Iron Station With Preheater.
A Bluetooth enabled CMS 50F PLUS OLED Wrist Color Pulse Oximeter along with other medical devices.
Numerous hard drives, NAS stations, computer parts, etc.
All in one place! And usually either better pricing or very competitive all with great customer service.