Below are mods that are not for DOS or SNES.
Many DOS and SNES mods are available.

First One (2016), a Game Boy Color mod by Norbert

Jaffar24's Levels (2018), an Apple II mod by Jaffar24

PoP Hack (2019), a Mega Drive mod by "Let's play Gamer"

PoP: Special Edition (1990), an Apple II mod by The Doppleganger