Whether these emulators support operating systems for these consoles is unknown; it must be looked into further. Consoles without meaningful OSes are not included.
Nintendo Entertainment System – NESMac
https://emulation.gametechwiki.com/index.php/NESMac
Nintendo Game Boy – GBMac
https://www.macintoshrepository.org/10592-gbmac http://hp.vector.co.jp/authors/VA009321/index2.html
Whether these emulators support operating systems for these computers is unknown; it must be looked into further. PCs without meaningful OSes are not included.
Amstrad CPC – CPC++ (maybe more)
http://www.bricerive.com/cpc/cpcpp.html (for 68k and ppc)