I didn't add anything. I did change the unreformed norse and the reformed norse heretics (which I think is what Old Norse looks like after the reformation). They're on the left second row, with the Ulfing character. You actually ca't see them here, because I couldn't be bothered trying to event-reform norse to see them; they're the unreformed norse in red. Same goes for the Celtic heretics. The Internet claims it's represents Yggdrasil, but I wouldn't know whether it's symbol that was actually used historically or a neo-pagan invention. I kind of liked it. If you want, I can adapt the reformed norse symbol (which is the same you currently use) for them.
I also changed the cross of the Apostolic Armenians (in the lower right). Again, Google image search claims it's the kind of cross they would use, but I'm not very knowledgeable in that regard either. I'm the least happy about that symbol as well, despite spending the most time by far on it... and it's certainly the one that will come up most often in actual play, too!
Here's what the individual symbols are for clarity:
- Celtic, Celtic Reformed, Kemetic, Kemetic Heresy (actually only Atenism ATM, so perhaps change it to the suns-and-hands symbol he should have?)
- Norse, Norse Reformed, Waldensian, Cathar
- Manichaean, Mandaean (Manichean heresy), Druze, Yazidi
- Bogomilist, Messalian, Apostolic, Apostolic Heresy (Paulician and Tondrakian)
If you know a symbol appropriate for the Lollards, be free to tell me and I'll make one

.