You can't just go out and buy one, but there are millions of AMD Ryzen chips with a known flaw in their BIOS and PSP signature-validation routines just ripe for a PSP-Cleaner type application. Go forth and be fruitful.

https://community.amd.com/community/amd-corporate/blog/2018/...

https://blog.trailofbits.com/2018/03/15/amd-flaws-technical-...