Depending on the player's faction, a familiar could emit different small cosmetic appearances:
Demon Familiars emit flame particles
Undead familiars appear ghostly (as if their model is see-through)
idk what to add for the other two
Casting Camouflage on the familiar will conceal these cosmetics, making them look like a regular mob (could even hide the name tag), and recasting it will reveal them again.
Optionally every familiar could emit particles depending on faction, and have their model somehow influenced as well. Just to give some customization options.
Depending on the player's faction, a familiar could emit different small cosmetic appearances:
Casting Camouflage on the familiar will conceal these cosmetics, making them look like a regular mob (could even hide the name tag), and recasting it will reveal them again.
Optionally every familiar could emit particles depending on faction, and have their model somehow influenced as well. Just to give some customization options.