Next to some retro Steve Austin tees that look quite tempting, the easy answers are the iconic 3:16, DX and even NWO shirts from the 90s. I think you could wear those anywhere and people would still kinda get it, you know? Not only because they're from a time where wrestling was at its most popular, but also because the designs were simple and just good looking so you could easily match it with the rest of your stuff.
Try and style a modern day shop item with your outfit and you'll soon realize you're doomed. They just put too much on these suckers now, I don't need a big graphic on the front and on the back next to a big "WWE Authentic Wear" badge, that's overkill