Subject says it all but just to elaborate any pitch with no break is counted as a fast ball correct? If a pitch is not a fast ball it qualifies as some sort of breaking ball.
I dunno that knuckleball counts as a breaking ball…but it definitely is not a fastball.
Changeup?
The knuckle ball and change up have been mentioned. There’s also the (e)ephus (it’s spelled both ways.) or blooper pitch. In Japan they throw something called the gyro ball which spirals like a football is thrown. There are many other names like forkball, palmball, and foshball, but those are just types of changeups.
It should also be pointed out that technically a fastball also “breaks”. It’s thrown with an overhand rotation that causes it to fall less rapidly than it would have if the ball had no rotation at all. Hence the somewhat misleading term “rising fastball”.
The categories are not clearly defined; the best way of thinking about it is to ask how each pitch is designed to work.
Fastball: Thrown for maximum velocity. Generally this means it’s more or less straight, with no break to it; however the most effective pitchers do have a little bit of “movement” on their fastballs, just coming from the unique way each holds/throws the ball (Three-Finger Brown being the peerless model of this). Pitches like the “cut fastball” or the “split-fingered” fastball are intended to have movement, but they are still fastballs because they are thrown hard.
Breaking Ball: Any pitch whose effectiveness comes primarily from movement. Some, like sliders, are thrown almost as hard as a fastball. Others, like knuckleballs, are thrown very slow indeed. But they all are designed to beat hitters because of the “break” of the pitch. Curveballs, sliders, screwballs, knucklers, etc. all go here.
Change-up: Is used two ways. In one sense any pitch that is not a fastball is a change-up, in that it is not thrown at the typical speed. But it also refers to a “straight change,” which is the counterpart to the fastball: a pitch whose effectiveness comes primarily from how slow it is. Of course, to be effective with a straight change, it helps a lot to have a respectable fastball to maximize the discrepancy, and it’s absolutely to have good control: throwing 95 gets you a margin of error that you don’t have at 75. Making sure your arm motion looks the same as your fastball is important, too. Plenty of pitchers rely heavily on the straight change; more now, in fact, than in years past AFAICT.
But again, a lot of the categories here blur together. Some guys throw two different kinds of fastballs, or two different kinds of changeups, or a Fast curve" and a “slow curve.” Etc.