Sonic 3 & Knuckles - The Cutting Room Floor

Sonic Origins/Sonic 3 & Knuckles - The Cutting Room Floor

Sonic the Hedgehog 3/Beta elements, Sonic Wiki Zone

Sonic Style Sprites - Original and Custom v9 by Abbysek on DeviantArt

News/Sonic Month Part 5 - Before Hard Times - Sonic 3 (MD) - Hidden Palace

Early Sonic 3 prototype found, features major differences to the final game

Knuckles Chaotix on Sega 32X, the psychedelic Sonic-adjacent game that at least deserves to be preserved in some form of modern port. More people need to develop their own opinions on it

Sonic Origins/Sonic 3 & Knuckles - The Cutting Room Floor

Sonic the Hedgehog CD (2011) - The Cutting Room Floor

Sonic 3 Prototype With Lost Content Discovered - IGN

Melting Pot Commentaries - The Face in the Book