Sonic X-treme - Wikipedia

Sonic X-Treme, Wiki

Sonic X-treme - Wikipedia

Editing Sonic the Hedgehog 4: Episode III (lost build of cancelled sequel to episodic platformer; mid-2010s) - The Lost Media Wiki

Sonic Dash – Wikipedia

Fans Resurrect a Long-Lost Sonic the Hedgehog Game

I found the most well-known Sonic Iceberg underwhelming, so I took my own crack at it. : r/SonicTheHedgehog

Sonic X-Treme, Sega Wiki

Sonic Adventure - Wikipedia

Sonic and the Black Knight - Wikipedia

Sonic X-Treme Revisited - IGN