Sonic Jr. (lost build of unreleased Sega Pico game; existence unconfirmed; 1994) - The Lost Media Wiki

Sonic Boom (non-existent lost episode of animated TV series; 2014

Sega Pico, Sonic Wiki Zone

Sonic Boom 2013 (lost livestream of Sonic the Hedgehog

Editing SegaSonic the Hedgehog (lost build of cancelled 32X port

Sonic the Hedgehog (lost build of cancelled Amiga port of Sega

Sonic the Hedgehog 2006 (lost build of Tokyo Toy Show tech demo of

Editing Sonic the Hedgehog (lost build of cancelled Sega CD port

Sonic the Hedgehog (lost complete build of Xbox 360/PlayStation 3

Editing Sonic Riders (lost build of cancelled Game Boy Advance

Sonic the Hedgehog Gameworld (Video Game 1994) - IMDb

Sonic Saturn (lost build of cancelled Sega Saturn prototype of

Sonic Saturn (lost build of cancelled Sega Saturn prototype of

Sega Pico Game: Sonic the Hedgehog's Gameworld (1994) Japanese

Sonic X-Treme (found build of unreleased SEGA Saturn platformer

Sonic DS (lost Nintendo DS tech demo; 2004) - The Lost Media Wiki