Oscar Isaac hints at a third possible Moon Knight suit for the hero's Jake Lockley personal.  

Steven Grant, a mild-mannered gift shop employee suffering from blackouts the two alters of a man with Dissociative Identity Disorder (DID).  

In the show, these personalities also have the ability to summon their own respective Moon Knight suits.

When in control of the body, Marc is able to summon the Moon Knight suit typically associated with the hero 

while Steven can transform into a more up-scale suit-wearing persona known as Mr. Knight. Moon Knight episode 3 hinted at a third more violent identity other than Marc and Steven  

Isaac has already teased the possibility of a third Moon Knight personality in the show, who may even get his own suit as well.

If Moon Knight does introduce a third personality for Issac's character, he will very likely get his own suit as well.  

Marc and Steven each have their own suits as Moon Knight and Mr. Knight, so it would make sense that a third personality would have a third costume of their own.