Melee Guards
Mage Guards
Archer Guards
Healer Guards
Shadow Unit <---I think this is a pretty cool idea, they'd be used to take out high-risk targets. They'd be like a special ops squad.
Different Ranks <---They should have different armor, weapons, ability, certain ranks should have horses (if there are horses)
Diverse Guards
Mounted Guards <--- If there are horse-drawn carriages, a horse in the trailer, and we still can't ride horse... I might be pretty disappointed.