Every sort of microcontroller/breakout board imaginable. I’m fond of the nanoCH32V305 (144MHz RISC-V CPU, 32k RAM/128k flash, and GPIOs for days)
Soldering project kits. I bought a NTP capable clock kit to learn SMD techniques, then discovered that the Chinese market has no need for time zone support, but I had little need for the time in Beijing.
There’s a surprising amount of miniature stuff there-- terrain parts for model railways, or dioramas or wargaming. The actual model railway stuff seems sort of thin on the ground, mostly resold and expensive foreign brands or toy grade stuff.
I got one of those ominous looking wire-stripper-cutter-tools and rather like it.