2 infusions
You can slot as many auras as you like. The effects are unpredictable and are affected by armor, dyes, and (if you have them) legendaries.
The only limitations are that some can only be slotted into exotics (Halloween’s poly-lumi black, green, orange, and teal + queen bee + Chak Egg Sac) and others must be placed in infusion slots (ghostly, phospho, winter’s heart) and one only fits in the ascended amulet’s enrichment slot (koda’s flame).
John Smith: “you should kill monsters, because killing monsters is awesome.”