RE: Bretonnia
Right or wrong my Bretonnians have 1 theme.
It is based around the Lady of the lake.
All characters have green clothing/barding, the armour of all characters and their mounts is gold.
All Damsels are wearing green, they also have green swords.
All Grail knights have green clothing and barding, gold armour.
The green knigh is.. pink! Not really

He is green.. He is a servant of the lady as are the Grail Knights and damsels so it seemed like a suitable theme to run with.
The shield design on every knight and every horses barding is half blue, half red.
Knights errant wear blue and red, including their barding, silver armour.
KOTR, silver armour, black clothes, barding, champions have green erm... tassles?
Peg knights, also silver armour, and black clothes, barding,but gold armour on the pegs.
All peasents have the red and blue shield, but wear yellow and red.
The whole thing has a bit of colour to represent ranks, gold and green for the lords and Grail knights, black for the pegs and kotor, blue and red for the Errants to suit the shield.
It looks like a combined force, they all use the main scheme in some way or another.
It is "wrong" but I do not care. I honestly think that painting 15 KOTOR unique colours is A, confusing, B unnapealing, they look like random folks just turned up to fight, that may be "correct" but I hated it.