Photo & owned by Shadouge

Here are 2 pair of boxers underwear with an all-over Sonic theme. It's rather creative, using different poses for modern Sonic, but leaving some of them as black/white line art, while having others colored. The close repetition of the art makes it into a type of pattern. The modern Sonic logo appears on the waist band, and it's likely that the leg bands & waist are elastic as well for the black pair. The use of gray keeps it from looking too busy in both cases. They're actually likely just a variant of eachother, so you'd be going for the style/color you prefer. This is available at: New Look. 

 Photo & owned by Shadouge.

This pair of modern boxers underwear has a Japanese theme. It has 2 poses for modern Sonic scattered all over. The background has red and yellow rays (possibly similar to 'rising sun' type rays) You can also see "Sonic" & "Sonic the Hedgehog" written in 2 different fonts in Japanese as well. The modern logo is an embroidered piece on the elastic black waist band. This is available at: New Look.

 Photo & owned by Shadouge.

A pair of underwear that will stand out from the rest in a collection! This one uses comic-book style screen-tone dots for the background, & a big splashy Sonic graphic, with a scattering of stars. It's not too busy or loaded with designs. It has Sonic's name in Japanese written vertically down one side, while the modern logo is printed large across the waistband. This is available at: River Island in 2011. 

 Photo & owned by Shadouge

This pair is rather confusing, with its overlapping black & white line art. If you look carefully, you can pick out 2 poses for modern Sonic, and a scattering of solid black stars. It may be busy, but it presents a very different look from the previous pairs of underwear. Found at New Look.

 Photo & owned by Shadouge.

This pair of modern boxers underwear has a Japanese theme. It has 2 poses for modern Sonic scattered all over. The background has red and yellow rays (possibly similar to 'rising sun' type rays) You can also see "Sonic" & "Sonic the Hedgehog" written in 2 different fonts in Japanese as well. The modern logo is an embroidered piece on the elastic black waist band. This is available at: New Look.

 Photo & owned by Kari.

Here are 2 pair of Sonic X themed trunks from NEXT. One has various Sonic X stock art scattered over it as a pattern, the other has a larger graphic with abstract blue/white background. What do these look like out of the package? The dot on the paper says "New Improved Fit"