I found all of mine on Amazon! https://www.amazon.com/Calhoun-Thrones-House-Tournament-Banner/dp/B012EVJ2WO
The Stark and Lannister banners came from Amazon. I think the Night's Watch and Targaryen ones are from Hot Topic.
Amazon https://www.amazon.com/Calhoun-Thrones-House-Tournament-Banner/dp/B012EVJ2WO
Here you go!
https://www.amazon.com/Calhoun-Thrones-House-Tournament-Banner/dp/B012EVJ2WO
Stark Banner Link Here