I have a black PC Engine T-Shirt I will raffle if there is interest.
I bought it years back and wore it once quickly to try it on for size and it was too small for me, so it's basically new but sat in my draw for years.
There's no label with the size, the size I would guess is a medium. I usually wear a Large and the T-Shirt was a bit small for me.
If there's interest and I raffle it I would ask winner covers shipping.
The T-Shirt looks exactly like the one Happy Console Gamer wears in all his PC Engine videos