Here are 6 Sonic hoodie sweat shirts straight from the Sega Shop online. They are basically just 3 designs, and the other is a color variant of the first.
The first is "Sonic Rings & Wings" which is classic Sonic in the winged ring balancing a ring on his finger under the logo. These shirts are either a middle-blue or black, with draw string hood.

The next style is the Sonic Mania logo with colorful stripe in the background. It can be on middle-blue or black simple sweatshirt color. The last is more subtle with a 'chest logo' for Mania, but it has the blue, red & orange character face sihlouettes under it for STK. This is either black or a very dark navy blue to choose from. Each shirt is about 30 dollars & they appear in the summer of 2018 at the Sega Shop online. (They are exclusives to there)
This is a pretty standard selection. None of these bring anything new to the table, so they're a good choice for a casual clothing person or a beginning collector. The Mania items are nice as a celebration for the well liked game.