Risur: I've wanted to have something druidic / celtic to represent their traditions and relations with the Fey, possibly also some stars for their Skyseers. Thought about Gondor's flag, but found this one instead on reddit's r/vexilollogy.
Danor: something french with a representation of tieflings - so something with horns. Chose Odin's horns symbol, which in Zeitgeist world will be know as "trihorn", an emblem of House Jierre / Pragati philosophy. Chose flag of Plantagenet England with trihorn in place of their lions, lilies stayed to give those french vibes.
Ber: something representing their beastial nature / semi-tribal society / racial divergence. Historical flag of Moldova works quite well - a bull (a minotaur?), several smaller symbols (main tribes?) and an overall rustic feel.
Elfaivar: something oriental and floral. Historical flag of Japan's shogunate works well, changed color to violet to give a more esoteric feel.
Drakr: something ominous and esoteric to represent their necromantic traditions (black and white colors), runes to show their dwarfiness (Valknut with futhark letters) and scandinavian cross because of their north european fluff.
Crissylyir: flag of the Teutonic Order with a Triegenes' hook instead of an imperial eagle. Fanatics on their crusade, plain and simple.