This article found ATMega328s chips that were actually buck voltage regulators: https://www.sparkfun.com/news/395
Here's an STM32 fake that "works", but has various issues (some serious) listed near the bottom: https://github.com/keirf/Greaseweazle/wiki/STM32-Fakes
Somewhat funny, the very bottom of the page above mentioned that "Note that this chip fixes Erratum 2.3 of genuine STM32F103". So the clone is arguably less buggy than the genuine STM32F103, at least in one aspect.
This article found ATMega328s chips that were actually buck voltage regulators: https://www.sparkfun.com/news/395
Here's an STM32 fake that "works", but has various issues (some serious) listed near the bottom: https://github.com/keirf/Greaseweazle/wiki/STM32-Fakes
Somewhat funny, the very bottom of the page above mentioned that "Note that this chip fixes Erratum 2.3 of genuine STM32F103". So the clone is arguably less buggy than the genuine STM32F103, at least in one aspect.