Mecha Sonic (Sonic 2 GG) by MarcosVargas on DeviantArt

ArtStation - Mecha Sonic (Sonic 3 and Knuckles)

The Mecha Sonic Story ▸ All FOUR Versions Of Mecha Sonic

I drew MECHA-SONIC from Sonic 2! : r/SonicTheHedgehog

IDW's Mecha Sonic MK2 - S&K Style! : r/SonicTheHedgehog

I get confused with their names. : r/SonicTheHedgehog

Mecha Sonic MK II (TheIronJedi), The Headcanon Island Wiki

Mecha Sonic Sprite Sheet by TheKnucklesMainG4 on DeviantArt

Sonic 2 Character Designer Shares Interesting Tidbits About Tails, Super Sonic, Mecha Sonic and More! – Sonic City

Unseen Sonic the Hedgehog 2 Art by Yasushi Yamaguchi Comes To Light - Sonic Retro

Knuckles vs Mecha Sonic by thewax70 on Newgrounds