the best (resource) for wool felt- which is what you are seeing patterns for is
thrift stores/yard sales---purchase items that are 100% wool- you can get alot of wonderful wool from a man's wool coat! take your items home- de-construct them- remove buttons/zippers, cut away the seams- small items place in a mesh laundry bag- larger items just do alone- toss into the washer with hot water & some detergent- wash on a long- cycle- with lots of agitaton- rinse on cold- toss into a hot dryer- when your items come out of the dryer you have felted wool ready to be cut up & used for wool applique, and any other projects that appeal to you.
it is common to see prices of $20 up to $60 a yard for the same felted wools in quilt shops.