As you might know, Sonic has not only been featured in games but cartoons as well. In total he's been in about 4 different series. All based on him. Oh, and he's been in one movie too. This is the index of all his cartoons and their info.

Before SatAM | Sonic The Hedgehog(SatAM) | The Adventures of Sonic The Hedgehog | Sonic Underground | Sonic X | Sonic OVA