This poster is both uncommon & sought-after.
It's a Sonic Adventure 1 retail poster that's pretty unusual. Instead of screen shots, head lines, big character art or console images, it's all just black. The only design is the Sonic Eyes & Grin (Later got called the BDG Big Dumb Grin) right in the middle. When SA1 was first being advertised, a lot of the promo materials just had the green eyes/BDG as the graphic, though it was later phased out. The bottom has some small text in white for the console, title, likely website, and release date. Being all art (however minimalist) this poster makes a big statement in stores or in the home.