Is this tee a little bit cheating?
Maybe. The all black shirt has a list of names in a simple sanserif font & different colors. It lists Sonic, Tails, Knuckles Amy & Dr. Eggman, each in the character's color. Without an image....people who had no idea about video games wouldn't know what was going on with the tee.
It's an ok idea, and may count for 'subtle-Sonic' category...and it's unique (in official stuff) because it's also a bit of an "Almost-bootlegger" tactic because the words themselves aren't copyrighted...they're only copright if they refer to the character WITH a picture of it OR the whole name of the character with "Sega" or something. After all, there's plenty of people named "Amy" without infringing on Amy Rose & "Tails" is just a plural noun. So you don't even need to hold a copyright to legally just put words on a shirt & say it's for fans. That's why this one is a bit odd.

This tee could be both modern and classic, but since the characters all appear in the classic universe, they get onto the classic category.