Four Seam Fast Ball.
Fingers are evenly spread along the top seam of the ball. Some pitchers will need to place all four fingers on the seams. You can use a two seam fastball, but a four seam generally will give you more downward movement.
Curve Ball
Some pitchers like to put a bend in their thumb on a seam to create more spin. The hand is underneath the ball to produce the four seam rotation.
Knuckle Curve
Thrown as a fastball with index finger tucked. This is an inbalance pitch whereas the ball will come out of the hand with the sideways spin. Always remember to push the tucked finger out hard and fast at release.
Four Seam Rise Ball
Held the same way as the curve, but the wrist is not bent. Some pitchers like to use the thumb in a tuck position to create more spin. Some pitchers use a two seam.
Knuckle Ball
Knuckles can be tucked on the seams, or you can use your fingertips, or a combination of both. The release is simply by opening your hand.
Drop Ball.
Middle finger is behind the seam to create a top spin of the ball. Some pitchers use a regular four seam fastball hold to pitch their drop ball.