I may be the one Ricohard mentioned above, I spent the first couple of years of Empire collecting all the heraldries.
(Amusingly, “Heralds” in game are the messengers and envoys of the Eternals… so if you say you’re training to be a Herald, several people twitch and try not to drag you off for interrogation )
I did collect all the symbols extant in play at that time, so there’s a few groups present now gone, and a few not in it. That character died before doing all the illustrations, but I dropped a copy off with the militia and a couple of other groups.
There is not a formal College of Arms, and there is not the careful selection of symbols, edgings, and quarterings that RL heraldry developed. Given that heraldy tends to be most important to Dawn, Highguard, Urizen, League, and maybe then Wintermark, (and then the rest) in that order, there isn’t a huge demand for it.
For a group heraldy: Check it’s appropriate for your nation, check that no-one else is using something very similar*. Some distinctive colours to be easily applied are a good idea, as is a symbol with a history/story behind it (there are some excellent examples of these on the field, I can suggest some for comparism if you like).
[There are 6 groups using a tower/castle as a symbol, 4 different ones with pheonixes, 3 variations on crows, and I lost count how many Navarr groups have vines/thorns/brambles…]
Then decide how much you’re going to display your symbol. A banner, little pennants, sashes, tabards, belt tags, shields, embossed into equipment… they’ve all been done, but as mentioned it’s mostly Dawn (and Highguard) who are likely to plaster their symbols on everything.
You may also want to discuss any variations. There’s a few houses in Dawn which have a theme and variations on it. Example: House De Gauvain: Majestic winged beast and roses: (Pheonix with a wreath of roses) (Eagle carrying a rose) (Dragon above three roses) (griffon wearing a crown of roses)
Don’t worry too much about this sort of thing. A clear symbol is nice but not essential. And if you like you can always leave it an event or two before sorting out and displaying your symbology.
Happy to discuss this further