OCRemix released a new remix album celebrating "25 Years of Sonic the Hedgehog" that adds up to 23 tracks over 3 albums that you can download or stream right now for free. The album remixes the game music from Sonic the Hedgehog, Sonic the Hedgehog 3, Sonic the Hedgehog (GG), Sonic Lost World, Sonic & Knuckles, Sonic Advance 3, Sonic the Hedgehog 2, Sonic Adventure, Sonic the Hedgehog (XB360), Sonic Heroes, Sonic Rush Adventure & Sonic Colors. Apparently there have been a ton of Sonic games over the years and this album aims to pay tribute to them all.

http://ocremix.org/album/79/speeding-towards-adventures-25-years-of-sonic-the-hedgehog