Sonic's Timeline SRB2 Message Board

First of all I'll mention I wont count spinoffs as mainline cannon games (Sonic Rush, Mobile Sonic games, Sonic Racing games) I'll count the storybooks as the gameplay has kind of a development of an early boost (although as someone who played them I must say that those boosts were crappy)

Tyson Hesse Sonic SRB2 Message Board

Prerelease:Sonic Robo Blast 2 - The Cutting Room Floor

Sonic Robo Blast 2 (3D Sonic fangame in development for 20+ years) releases huge new update. [New July 2020 update.], Page 10

SRB2 Kart: Player Bot Mod (Update). Some new maps, concepts and etc.

sonic adventure 1997 prototype v2 (real) : r/SonicTheHedgehog

Sonic: Lock & Load » Index

Sonic (SRB2) Minecraft Skin

Sonic Robo Blast 2 Kart - Sonic Retro

Sonic Robo Blast 2 (3D Sonic fangame in development for 20+ years) releases huge new update. [New July 2020 update.], Page 10

Sonic Robo Blast 2: The Past (Video Game) - TV Tropes

Sonic Robo Blast 2 - The Cutting Room Floor