Photo & owned by Bianca

This Segaworld shirt could only be bought out of Segaworld London. (So it's uncommon!) It's a nice mottled gray tee with "Segaworld" written up one side, in the Sega font. It uses the seldom-seen Japanese sitting Sonic stock art. The sleeve has a special tag, letting everyone know where it came from. This is a great old shirt, made even better by the uncommon art choice.

 Photo by: Matthew Senn , owned by Andrew Senn

These are small children size vests. They're only large enough to fit 3 to 5 year olds or so. These are from Marks & Spencer, and the tag (middle) says "St. Michaels for Marks & Spencer". The fabric is black, but has a rather busy design. There are little yellow stars, various Sonic stock arts, and 'screen shots' of Green Hill. This was released in 1992, so pretty much right after Sonic really started getting popular. 

This tee comes across as rather busy, with its all-over design and mis-matched sleeves. (one is blue, the other orange, while the collar is all orange) It has a sort of abstracted cityscape for the background (a level like that didn't exist in the time of Sonic 2...which is when this was made) It has the old 'thicker spikes' version of a Sonic stock art leaping over a banner like thing with his name on it, while a star bumper, the logo, & Tails are placed below. Look at unusual running Tails, he's quite on-model, orange (as he should be) and shown in an interesting/seldom seen pose. For some reason, several of the game's timer clocks are scattered around at the bottom...even pixelated, like they were in the games. This is an unusual old shirt.

This is likely to be a genuine classic shirt, as the design is a little simple & strange. Various random colored wiggly lines go at an angle, while Sonic leaves horizontal speed lines behind him as he runs...but it looks like they've added a yellow Sega logo over where the feet / spinning feet effect would be for some reason. Is the interior of this shirt blue, or does it have blue trim for some reason? 

 Photo & owned by Kitsune Li

Here's an interestingly designed classic shirt. The whole thing is Sonic & Knuckles themed, with the logo in color, the S&K symbol in black & white plus line-art as the background with full color art for Sonic & Knuckles on the front. The art for them uses screen-tone dots for the shading and 'motion blur'. The Sonic is nicely shaded Stock art but Knuckles is rather wierd shaped in the body, & has little feet. The shirt is unusual because the symbol print is on both sides / everywhere.

This was made by The One and Only Clothes Co. and is copyrighted 1991 / 1992 . It is uncommon & was likely sold around the release of S&K the game. An interesting shirt with a unique look! 

 Photo discovered by @JapanAnimePosters on Instagram

Here's a charcoal-gray slogan tee with "Gotta Stride Clyde" at the top.
It features a fairly large full color graphic of toe-tapping annoyed Sonic under the phrase. If you look carefully, you can see he's on a background of very faint line-art/dark greenish? Sonic images. The classic logo & copyright are under his foot.
The "Gotta Stride Clyde" 'catchphrase' was really only attempted to be popular in the UK area, so it's no real surprise to find it at least on 1 tee. With a simple graphic & small slogan, this is a pretty typical classic tee. 

Here's a bit of an unusual shirt from the early 1990s...
It's style (white body with red collar & sleeves) is unusual, & so is the art. It has 'finger waving' Sonic, but his opposite hand has been changed/re-drawn (notice how fat it is) so he looks like he's leaning on that 'totem pole' like thing in the background. What other mistake can you spot? His arms are blue! The tower of wooden faces are very goblin-ish. Is it suppsoed to represent the 'totem pole' like items from the background in the game? It's a bit off, if so. Then, there are stars in the background like it's a 'night sky' but the shirt is white. Also, what's that wierd little green planet/moon up there? All these elements together makes for a confusing old shirt.

 Photo & owned by: Eddie Booth

This is a shirt by "Sonic GEAR" which is that brand that existed & stopped existing before SonicGear.org was created. This shirt has a slogan "Think Fast" & uses actual parts from Sonic 1 backgrounds, like the lif counter, timer, star bumper & lines. The art is interesting, as it goes from regular/shaded stock Sonic (arms crossed) to the last (right) image, which is a pixelated game sprite of spring-jump Sonic. The 2 inbetween have been altered to be progressivly more 16-bit pixel styleized. With this photo you can see the different sizes it came in. 

Here is a selection of 4 sweaters, all by Intarsia.
Intarsia is a Gary Kennedy brand. These are in childrens AND adults sizes. They are also actual sweaters, not sweat shirts. This means they're woven out of yarn, and have those 'jagged' type edges for the designs, and cannot get fine detail in the pattern. In the day when these were released, this kind of pattern and color was being done un-ironically, unlike today's "Tacky Christmas Sweater" trend, where the 'stitch' look is used as a joke type of effect.
The first red one has forward facing Sonic & his name in yellow, the next is yellow with 'finger waving' Sonic and his name in red vertically, the third is another but lighter yellow with running thumbs-up Sonic (and a speed line or two) & the last is white with a hip-up portrait of him just standing.
Do you notice something?
The running one has the BLUE ARMS mistake! The others are actually correct, with the beige arms, so how'd this one slip past the pattern maker? They're all the same brand, the same character---there shouldn't have been any confusion. These are thought to be a very early release, possibly before the time of Sonic 2.