I must admit, I've been struggling all morning with heraldry, signs & sigils. I don't find it a very accessible subject for providing value for characters - and I couldn't think of anything that was deserving of a very high status of research. Perhaps someone could suggest some directly practical element of heraldry that I hadn't considered.
Sometimes, it is best to consult the internet.
I have added one additional ability to the heraldry page: standard bearer. The rule is adapted from the hobgoblin monster listed in the original Monster Manual.
I do think it's nice with random rules like that are fitted into a larger scheme.