Being a list of merchants mentioned in the archives of the 12th Century Garb Yahoo Group over the years.
Pilgrim Badges and Pewter Accessories:
http://www.fetteredcockpewters.com/
http://www.billyandcharlie.com/
http://www.pewterreplicas.co.uk/
Fabric
https://www.fashionfabricsclub.com
https://www.silkconnection.com/
(Formerly JacquardSilks.com)
https://www.fabricmartfabrics.com/
Try http://www.dharmatrading.com/silk_fabrics.html
They have good descriptions of their fabrics which might help you decide on which to use.
Notions
hedgehoghandiworks.com
… owner retired. See this helpful link instead:
https://www.needlenthread.com/2017/03/where-to-find-hand-embroidery-supplies.html