From Fedora Project Wiki

HELLOTUX

HELLOTUX sells authorized shirts and sweatshirts with the Fedora logo. They are based out of Europe, but they ship worldwide. https://www.hellotux.com/fedora

An interesting Fedora Magazine article talking about how these are made.

Unixstickers

Unixstickers sells authorized goods (right now, just stickers) with the Fedora logo. They are based out of Europe, but they ship worldwide. See the ultimate pack, which contains Fedora stickers along with a number of other free software project stickers. http://www.unixstickers.com/fedora