Personally, I have two, but I think some people have been going in for a third.

[Reaching into a small bag he had on his person, Adrien took out his iMog slate and opened the Jobs to show Hope.] You can only have two equipped at once, but people have been putting a third on Reserve. I know you can change between the two you currently have equipped in battle, but I'm not so sure how having a third one works yet.