New to BTs, Question about kitbashing

Greetings Brothers!

New to Black Templars, and using the SM half of the Armageddon launch box to start my BT army. I've built the standard Intercessors already, but was moving to the Vanguard vets and was curious about what you all might use for bits to snazz them up and make them more "Templar"? Keep in mind the Armageddon launch box is basically all I have right now so I don't have any spare SM bits (have been an Ork player). Are there Etsy shops or elsewhere where I can get my hands on SM bits without buying multiple Sword Bro kits to part out, etc? I have the Black Templar upgrade kit, and it has a bunch of good shoulder pauldrons, but that's about it. Thanks!