Modifications that add, replace or modify Characters of Megadrive Sonic titles will be listed here.
- KTE in STH1 : Allows you to play as Knuckles the Echidna instead of Sonic the Hedgehog in Sonic 1, with all his movesets – by Stealth (Link)
- Sonic Classic Heroes : adds the teams gimmick from Sonic Heroes to Sonic 2, allowing you to quickly switch between 3 characters whenever you want – by flamewing, ColinC10 and Various others (Link)
- Knuckles’ Emerald Hunt : by MainMemory, Based on Sonic 2 Adventure Edition, focuses entirely on Knuckles hunting for Emeralds through all the Zones of Sonic 2 (excluding Sky Chase and Death Egg), along with a few extra levels. (Link) (Netplay Link)
- Sonic in Chaotix x32 : Changes Mighty to Sonic – by JJFTails, KojiChao, SGR (Link)