Hacks - SHADOW In Sonic 1 (Original Levels) TRaiNoR

Sonic the Hedgehog, Heroes Wiki

Shadow in Sonic 1 v1.1 (S1 Hack) : Free Download, Borrow, and Streaming : Internet Archive

Sonic the Hedgehog (2006), Sonic '06

Literacy on EeveeFanClub - DeviantArt

Sonic Hack - SHADOW in Sonic 1 TRaiNoR

Sonic The Hedgehog 2 Review

Shadow vs Knuckles

Shadow, SEGA Heroes Wiki

Sonic Hack - SHADOW in Sonic 1 TRaiNoR

Sonic the Hedgehog hack: Shadow in Sonic 1

Games - Sonic the Hedgehog 2

Sonic All Transformations #3 - Episode Of Shadow (Sprite Animation)

Another) Shadow in Sonic 1 Sonic and Sega Retro Forums

I know people take issue with IDW Shadow, but the comics really do right by so many characters (some spoilers for the comics included) : r/SonicTheHedgehog