[microtherion]

Apple products have already been mentioned, and one of the risks there is that counterfeit chargers tend to cut corners in their design and thus can be much less safe.

Another category I know of are Arduinos. It has often been noted that, since Amazon warehouses commingle stock of "identical" products from different vendors, the reputation of the marketplace vendor won't even protect you, since the vendors have no control whether you got a genuine item or a counterfeit off the pile (Not sure whether that is an ongoing practice, but it was widely reported a few years ago).

[contingencies]

AFAIK original Arduino hardware is not a copyright design, and has actually been improved upon for most deployments (ie. made cheaper) in China, eg. by replacing with cheaper UART chipset.

[icebraining]

Nitpick: the Arduino hardware design is copyrighted, but released under a CC license.

[microtherion]

And the Arduino designers do not object to people copying the electronic design (even less so if there are design changes like substituting in a different serial chip). What they ARE objecting to is people copying the branding and graphics (down to the "made in Italy"): https://blog.arduino.cc/2013/07/10/send-in-the-clones/

Still, different serial chips mean different device drivers, so one product shouldn't be sold under the other's name.