There are no monasteries on Athas. Rather, a style of fighting emerged from the gladiator pits in response to a demand for unarmed combat, and from those combatants, nobles and templars bred in psionic abilities to create masters of the body. Due to their popular crowd appeal, enough have been granted freedom that they have spread out and trained others, or sought greater fame and fortune in the sands. A master monk is as rare as steel and just as dangerous.
Psionic monk gladiators are considered by their owners to be less trouble than a true psionicist because their powers tend to stay restricted to the physical form. A monk who displays a greater array of powers might be put down instead.
Use the defaults from the Player's Handbook or Xanathar's unless changes are mentioned below. From any other book please check with the DM.
Way of the Shadow. Does not exist.
Like a cleric, the monk gives herself to a particular element (see Cleric) and is subject to the same loss of all class powers if violating tents of that element.
A version of the sun cleric, subject to the same loss of all class powers if violating tenets of that element.