Here's a set of 6 Sonic Forces Keychains.
These are supposed to be from an event of some kind, maybe a release or a convention. They are likely to be acrylic or rubbery with CG art printed on them. Each is die cut into the outline of the character. You could get classic Sonic, modern Sonic, Shadow, Knuckles, Tails or Infinite.
Noteable about it is the gloomy look of Classic Sonic who is almost never portrayed that way, as well as concerned Tails.