Oxford Pennant
There's nothing more I love than classic, simple, old-school, vintage sports memorabilia and Oxford Pennant is just that. They design and manufacturer vintage wool & cotton pennants that are inspired by American sports traditions. It is run by Dave Horesh & Brett Mikoll in Buffalo, NY. Here's some of my favorites but there's bunch more that can be purchased here.
One detail I also enjoy are the sketches on the product page. Personally, I think it's always nice to see where a design starts.