Sonic CD - Sonic's one and only outing on the Sega CD still holds up well as a great Classic Sonic title, even if the series has long since grown out of the aesthetics found in CD in particular.
It's great for those who wish to play as their favorite character.
SONIC R SUPER SONIC RACING SIMULATOR
Sonic Speed Simulator - While it may be a Roblox game, Sonic Speed Simulator is an officially supported fan project by Sega that allows fans to run across multiple different iconic levels as a number of Sonic's friends.
Sonic and the Black Knight - While some consider Black Knight's medieval theme to be bizarre, fans tend to look to this game as the perfect example of how Sonic stories should be, offering a great experience to players who wish to give it a try.
Sonic Lost World - This game is known for slowing Sonic down for the sake of more tight controls that allow players to freely explore a unique world that values exploration over speed with exclusive parkour mechanics.
Sonic Riders - While it received mixed reviews when the title first launched, Sonic Riders has been fondly remembered by fans for its fast-paced racing dynamics and unique style, offering a unique experience not found in other Sonic racing games.
Even though Colors: Ultimate had a rough launch, patches have since fixed the issues fans suffered from, and it's now the most accessible way to enjoy the once Wii exclusive title.
Sonic Colors - Sonic Colors has been fondly regarded as one of the best Modern Sonic games, and has recently seen a remastered rerelease with Sonic Colors: Ultimate.
Due to the passion put into the project, it's arguably the best of the offerings Classic Sonic fans have to choose from.
Sonic Mania - Out of the many 2D games the franchise has to offer, Sonic Mania stands out as it was made by fans brought on by Sega themselves.
While hard to find, these games are most definitely worth picking up.
Sonic Advance Trilogy - The Sonic Advance titles for the Game Boy Advance are more often than not praised for what they offered 2D Sonic fans back in 2001 to 2004.
Players still praise the daytime stages, but the use of Sonic the Werehog and the game's medal system are seen as the game's biggest flaws.
Sonic Unleashed - This important 3D title changed the Sonic formula for years to come.
It still holds up as an important part of the series even ten years later.
Sonic Generations - A unique game made to celebrate Sonic's 20th anniversary that features both Modern and Classic Sonic play styles across many different levels from previous releases.
Sonic Adventure & Sonic Adventure 2 - Sonic's first proper foray into 3D, and arguably one of the series' most fondly remembered titles, these are commonly considered must-plays.
All four first mainline games can be purchased as a set in Sonic Origins together, completely remastered.
Sonic 2, Sonic 3 & Knuckles- Considered to be the best of the original 2D Classic Sonic titles, these two have aged considerably well compared to the first game.