Most ETH shirts are just the diamond and "Ethereum." I wanted a new take on it, so I took an ETH QR code as my base and designed this. It's up at Redbubble only for now but I'll be putting it out wider if there's interest.
https://www.redbubble.com/people/bradvance/works/26798328-ethereum-qr-style?asc=u
There's even a throw pillow :)