Some monks are special cases. They aren't typical, and they aren't particularly common. These monks are Aasimar, and they can harness special abilities because of their celestial heritage. These monks are usually treated specially and favored in their monasteries, but they are natural outcasts. They often leave behind their monastic lives, and become Monks who follow the Way of the Celestial. 

(This is a subclass mainly meant for my own personal character, but I thought some may find it interesting. It is designed specifically for Aasimar characters, but please feel free to modify it to fit your own characters! It's also definitely a work in progress and will likely receive many edits in the future.)

Open Hand Technique

Starting when you choose this tradition at 3rd level, you can manipulate your enemy’s ki when you harness your own. Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, you can impose one of the following effects on that target:

• It must succeed on a Dexterity saving throw or be knocked prone.
• It must make a Strength saving throw. If it fails, you can push it up to 15 feet away from you.
• It can’t take reactions until the end of your next turn.

Rigorous Studying

At 3rd level, thanks to intense and extensive studying, you gain proficiency in the history and religion skills. If you already have a proficiency in either of these, your proficiency bonus for that ability check is doubled.

Celestial Blessing

At 6th level, you have been blessed by a divine power and now have the ability to heal yourself and others. Replacing your Healing Hands ability, you now have a pool of healing power that replenishes when you take a long rest. With that pool, you can restore a total number of hit points equal to your monk level x 3. As an action, you can touch a creature and draw power from the pool to restore a number of hit points to that creature, up to the maximum amount remaining in your pool. 

If at least half of the hit points in the pool still remain, you can spend all of the remaining to produce the benefits of a lesser restoration spell. When you reach 11th level, you can produce the benefits of a greater restoration spell this way, and can produce the benefits of a lesser restoration spell with at least a quarter of the hit points remaining. 

Divine Attacks

At 6th level, you can choose to have your unarmed strikes and monk weapons deal radiant or necrotic damage instead of the normal damage type. 

Ki-Empowered Abilities

At 11th level, your ki is able to give you certain advantages in many aspects of life. You may now spend ki to gain advantage on ability checks. You may choose to use this feature after the dice has been rolled, but before learning any of the effects. It costs 1 ki to reroll an ability check you are proficient in, and 3 ki for an ability you are not proficient in. Once you use this feature, you must wait 1 hour before using it again. 

Celestial Ascendancy

At 17th level, your celestial influence has become even more prominent. You may now use the ability granted by your subrace (Radiant Soul, Radiant Consumption, Necrotic Shroud) an unlimited number of times. 

Additionally once you gain this feature, you can spend ki points to deal the additional damage more than once on your turn. It is 3 ki points per hit to deal this extra damage. After the first time you use the subrace ability, you must use ki in order to deal the extra damage.