Sonic Mania will have a Re-Release Update called Sonic Mania Plus which incluides Mighty the Armadillo and Ray The Flying Squirrel (both forgotten Sonic characters who made their first appearance at SegaSonic Arcade game while Mighty appear in the Knuckles Chaotix and both characters were forgotten by Sega)
and Meanwhile Sega announces a new Sonic in which is not sequel of recent game but a sequel Sonic R (yep that one obscure Sonic racing game in which the Tails Doll myth became a Creepypasta)