Best and Easiest pitches to add?

What do you guys think is the easiest yet most effective pitch to add to my arsenal. I am currently only throwing a good fastball and I need some movement. Thanks!

Circle change. If you have the dedication to work at it. It is not easy to learn. I read that in a survey of MLB pitchers asking them, “What pitch do you not throw but wish you did?”, the circle change was the most common answer.

I am trying to find an easy one to learn. And a change up doesn’t move as much as some of the other pitches.

CHANGE UP-> learn it- it will move and the change of perceived velocity makes your FB seem faster.

Change up or curve ball. Curve will add depth, change will makes the FB seem faster. Really need 3 pitches anyway.

No pitch is really “easy” to develop. But between the curve and changeup, I’d say the curve is easier. But in the long run, the changeup will probably be a more beneficial pitch. Try working with both.