The [[GBZ80]] (Sharp SM83) that powers the original [[Nintendo GameBoy]] is an in-between the [[Intel 8080]] and Z80. [https://gbdev.io/pandocs/CPU_Comparison_with_Z80.html Source] [[Media:GBCPUman.pdf|Game Boy CPU Manual]] [https://gekkio.fi/files/gb-docs/gbctr.pdf Game Boy complete technical reference] [https://youtu.be/GBYwjch6oEE Reverse engineering the Game Boy hardware] [https://youtu.be/HyzD8pNlpwI The Ultimate Game Boy Talk] [https://emudev.de/ Emudev (gb-si)] [https://github.com/c-sp/game-boy-test-roms Game Boy test roms]
However, Fun fact: More GBZ80 cores were produced for Gameboy hardware (118 million Gameboys and 81 million GBA) than all the Z80 chips produced for home computers and game consoles. The Sega Master System and Game Gear use a standard Z80 CPU. [https://segaretro.org/images/d/d6/SoftwareReferenceManualForSegaMarkIIIEU.pdf Master System reference manual] [https://segaretro.org/images/1/16/Sega_Game_Gear_Hardware_Reference_Manual.pdf Game Gear reference manual]
The [[KC Compact]] uses the U880, which is an unlicensed clone of the Z80 manufactured by MME. It was the most widely used microprocessor in the German Democratic Republic. [https://en.wikipedia.org/wiki/U880 Source]