I kinda like this idea a lot so I have some changes to make it better imo.
So:
1-
There are 6 stones in game and 17 plates, all from diferent colors, so if you mix them it gives you about 102 diferent colors, that could be the color of each aura. That makes 102 diferent auras
2-This quest would have 2 NPC's.
3-To make the quest you will need to:
Defeat the 1st NPC who has: Sunflora/Bellossom(Sun Stone), Nidoking/Clefable/Wigglytuff(Moon Stone), Victrebell/Vileplume/Exegutor(Leaf Stone), Raichu/Jolteon(Thunder Stone), Ninetales/Arcanine/Flareon(Fire Stone) and Cloyster/Poliwrath/Vaporeon/Starmie(Water Stone), all at level 130.
Then there is a NPC spawned at the map in 1 city only which must be found by the players, and it would say:
"Player:Hi
NPC:Hello Pokemon Master! Can I help you?
Player:Yes
NPC:I can add an "aura" to your pokemon.
Player:Aura
NPC:To add an aura to your pokemon, you must bring me: one stone and 10 plates from one type.
Player:Bye
NPC:Come back soon!"
The mix of the stone and the plates will result in the color wished by the player, so there must be a list with the plates and stones who give the 102 diferent auras avaiable at the website or forum. After bringing the plates and the stone the NPC says:
"Player:Hi
NPC:You're back! Do you have what I asked you for?
Player:Yes
NPC
ut the pokemon's pokeball that you wish to add an aura in the pokeball slot and then give me the "items".
Player:Items
NPC:Are you sure you want to add a xxx color aura to your pokemon?
Player:Yes.
NPC:Your pokemon has now a xxxcolor aura. Come back soon!
Player:Bye"
4-After giving one pokemon an aura, to give another auras to another pokemons, the player will have to battle the first NPC again and bring another stone and 10 plates according to the color that is wished by the player.
5-The minimum requiriment for this quest is:
-Level 120
This is my idea.