While tees and even sweatshirts were fairly common, outerwear such as this windbreaker, were not. This is a windbreaker style jacket (note the shiny cloth) with elastic cuffs and waist. The back has a combination of embroidery and felt-like material sewn on in a very large patch to form a rather odd-perspective for Sonic. Above, is a smaller Eggman/Robotnick head (his design here appears to be in the 'between' stages when they had not decided on his look outside Japan)
The jacket may be rare, but it has a rather dynamic look thanks to the large quality patch.
Photo by: JaQ . S
This is a little kid size Sonic sweatshirt. It has likely had all the art re-drawn from classic stock arts. Sonic's shading is somewhat unusual, and his hand is rather small. The Tails is clearly based off of the one that peeks out from behind the "2" in the Sonic 2 graphic...but it too is slightly different. Eggman (not Robotnick-ified yet) is shown peering over the edge of the ring that Sonic is in. It makes for a rather different looking presentation, along with the colored stripes on the sleeves and the over-all color mixture. This sweatshirt was not common.
Photo provided by: Rhia
Here is a promotional tee from the release of Sonic & Knuckles.
The S&K symbol is an absolutely marvelous feat of graphic design. The clean lines of the symbol and its instantly-recognizable characters are fantastic. Here, they didn't need to do any more than drop the symbol on the front of this white tee (the speck is the copyright) and release it. It stands as it is, without need of klutter or even a title.
Photo provided by: Rhia
This classic shirt adds a word and Robotnick to give the rather large design a different look.
Sonic's name appears in the classic logo, but then again at the bottom, with the word "Spin" to describe the crouched/ready to spin Sonic stock art they chose. Also, oddly enough, a small Robotnick appears near the bottom, but they've chosen to duplicate his graphic 3 times with overlap, perhaps to try and get a sense of movement out of the running Doctor. This shirt is uncommon.