Way of the Sun or Moon Celestial

Monks of the Way of the Sun or Moon Celestial are aasimars, who learn to channel their life energy into searing bolts of energy by harnessing special abilities of their celestial heritage. 
Monks who use radiant damage on their strikes are called Sun Celestials, and the ones using necrotic are Moon Celestials. 

Inspiration for subclass: Way of the Celestial by Tatepollock, Way of the Sun Soul and Celestia warlock.

Energy Bolt

Starting when you choose this tradition at 3rd level, you can hurl searing bolts of magical energy.

You gain a new attack option that you can use with the Attack action. This special attack is a ranged spell attack with a range of 30 feet. You are proficient with it, and you add your Dexterity modifier to its attack and damage rolls. Its damage is radiant or necrotic, and its damage die is a d4. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.

When you take the Attack action on your turn and use this special attack as part of it, you can spend 1 ki point to make the special attack twice as a bonus action.

When you gain the Extra Attack feature, this special attack can be used for any of the attacks you make as part of the Attack action.

Celestial Legacy

At 3rd level, you are able to activate the ability granted by your subrace (Radiant Soul, Radiant Consumption, Necrotic Shroud) as a bonus action and regain use of it after a short rest. You also gain proficiency in one skill of your choice. ( Flying speed for you Radiant soul feature becomes equal to your walking speed)/

Healing Light

At 6st level, you gain the ability to channel celestial energy to heal wounds. You have a pool of d6s that you spend to fuel this healing. The number of dice in the pool equals 1 + your monk level.

As a bonus action, you can heal one creature you can see within 60 feet of you, spending dice from the pool. The maximum number of dice you can spend at once equals your Wisdom modifier (minimum of one die). Roll the dice you spend, add them together, and restore a number of hit points equal to the total.

Your pool regains all expended dice when you finish a long rest.

Divine Attacks

Starting at 6th level, your unarmed strikes count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage. also you can choose to have your unarmed strikes and monk weapons deal radiant or necrotic damage instead of the normal damage type. 

Searing/Withering burst

At 11th level, you gain the ability to create an orb of energy that erupts into a devastating explosion. As an action, you magically create an orb and hurl it at a point you choose within 150 feet, where it erupts into a sphere of energy for a brief but deadly instant.

Each creature in that 20-foot-radius sphere must succeed on a Constitution saving throw or take 2d6 radiant or necrotic damage. A creature doesn’t need to make the save if the creature is behind total cover that is opaque.

You can increase the sphere’s damage by spending ki points. Each point you spend, to a maximum of 3, increases the damage by 2d6.

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.