I would use well known creature for fantasy monk styles... Creatures that the average monk order has a great chance of knowing about. In Real World, there is no Kangaroo style nor Sloth style. It should be the same in Fantasy world, so, unless the monk order is underground based (drow, derro, duergar...) I won't use aberrations like hook horrors nor rare undead like bodak.
That said...
* Griffon style : it's about attacking from above through a jumping charge, tripping your opponent and then either bringing powerful punch on his head while pinning him with the legs, or using swift deadly strikes to his eyes with two or three fingers. This is not a style for pacifist monks, but for the more battle-frenzied of them. Barbarians monks ?
* Treant style : Monks following this style train their bodies to endure hurts and wounds. This is mostly defensive style : you wait for the attack, soak it if needed, but exploit the moment when the enemy connect to catch him and then strangulate him. Another advanced aspect of the style is to focus inner energy (ki or psi depending of the edition you are using...) to project powerful blow at a distance or in the ground around you to trip your opponent.
*Drake swarm style : this rare style is the art of collaborating with your ally to act as one in battle. It has been developed by halfling monks to beat stronger and bigger opponents. It emphasis giving cover to your ally, swaping places quickly to confuse the ennemy, surrounding him, entering his space to attack him from below while your ally jump to reach his head, slowing, hindering the enemy to make his attacks less effective. It's all about being
very quick and negating the advantages and forces of your enemy.
* The succubus style is not for this forum, so I won't elaborate about it. Use your imagination.
