Below is some places that I have used for Dillon up-grades
https://inlinefabrication.com/collections/dillon
https://uniquetek.com
https://www.titanreloading.com/titan-reloading-products/easydial-small-bar
https://usa-shop.armanov.com/collections/dillon-550-upgrades
https://forums.brianenos.com/topic/279056-best-dillon-press-upgrades/
https://dramworx.com
https://ballistictools.com/store/dillon-press-enhancements
https://www.joferusa.com/
http://kmssquared.com/ufo550.html
https://lousgunwork.com/index.html