Here is a list of all of the main line Sonic the Hedgehog games in order of release, including where and how to play them.
Every Mainline Sonic The Hedgehog Game In Chronological Order
Tier list of every mainline sonic game. Is my list valid? : r/SonicTheHedgehog
I made a timeline with almost every Sonic game. : r/SonicTheHedgehog
The Complete List of Sonic Games in Chronological & Release Order - Cheat Code Central
Shadow ranks all of the main line Sonic games!
Sonic the Hedgehog 4: Episode I - Wikipedia
Ranking Every Mainline Sonic The Hedgehog Game - Game Informer
Best Sonic games ranked - the games to play before Sonic Superstars
Ranking Every Mainline Sonic The Hedgehog Game - Game Informer