Here are 2 black wallets for 2017 / 2018.
They both have the 16 bit pixel art style. The top wallet has a Green Hill type 'ground' but it's pretty featureless. The back has some gold rings, and they're trailing some pixel sparkles. The front has Sonic running, but he's really big (compared to the ground) and not running on it, rather floating out in front. They've also added some grayish pixel....dust? behind him.
The second wallet is a bit busier, it has angled rows of different sprites for Sonic, Tails & Knuckles. Each is shown rolling, standing, and running. The background is plain black.
Both of these are simple faux-leather bi-fold wallets with slots for cards and fold area for cash. These are Sega Shop items. They should be around 18.00 and only seen in the shop.