Howl Fabric is one of the most used brands by suit makers

https://www.howlfabrics.com/

I've mostly gotten my materials from Amazon and Hobbycraft in recent years, myself (though the latter doesn't do much in the way of furs these days..)

The howlfabrics that BelialGoat linked looks very promising, though! 👀

Idk where you live but in America you can get Fabric from Paramount Fabrics, Hobby Lobby, Quilters Headquarters, Walmart (rarely), and Michaels Craftstore will soon start. There are often local stores that you can look up that sell fabrics and call to see if they have Faux Fur. Joanns Fabrics and Crafts used to but they don't exist now and Amazon may have some.