Gettare, lanciare, tirare, scagliare all mean “to throw”. Which word is used as to throwing a ball? What situations are the other words used in?
This list is sorted by use frequency:
tirare: this is classical "to throw", by hand or by foot
lanciare: usually when the ball is thrown by hand
scagliare: this is very uncommon, it's usually used when you throw the ball against someone, and that's usually specified. "Gli ha scagliato la palla contro" is an example. Since it represents an offensive act, intended to hurt someone, its use is very uncommon for a ball.
Gettare (as buttare) isn't used with this meaning, it rather means "to throw away".