A fun one is some of the phone chargers on there. Someone at work bought one and found out quickly that there was 240V on the USB-C shell. They were lucky it didn't kill them. That was marked as CE / UL etc because the stickers are cheap.
Actually tested stuff costs money. Not a lot more but enough to push them down the ranks.
I've also had this experience; ordered a box of 10 chargers for $20 for the office, and of course they're built down to that price way below any standard of electrical safety. The "shell" was joined in a way that pulling on it to pull out the plug could detach the back leaving exposed live wiring.
Actually tested stuff costs money. Not a lot more but enough to push them down the ranks.