Okay, here goes...(skip to the end for the short version
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High School (NFHS): The pitcher shall not at any time during the game be allowed to use tape or other substance on the ball or contact points of the pitching hand or fingers; nor shall any other player apply a foreign substance to the ball. A pitcher who licks her fingers shall wipe them off before bringing them in contact with the ball. Under the supervision and control of the umpire, powdered resin or any comparable drying agent may be used to dry the hand. The pitcher shall not wear any item on the pitching hand, wrist, arm or thighs which the umpire judges to be distracting to the batter.
ASA: A defensive player shall not at any time during the game be allowed to use any foreign substance upon the ball. Under the supervision and control of the umpire, powdered resin may be used to dry the hands. Applying resin in the glove and then placing the ball in the glove is an illegal act. Resin must be kept on the ground behind the pitcher?s plate. A pitcher who licks their fingers must wipe the fingers off before bringing them in contact with the ball. A pitcher shall not wear any item on the pitching hand, wrist, forearm, elbow or thighs, which may, in the umpire?s judgment, be distracting to the batter. Batting gloves may not be worn on the pitching hand.
USSSA: The pitcher shall not wear any item on the pitching hand, wrist, arm or thigh that the Umpire judges to be distracting. If a pitcher wears a batting helmet while on defense, the outer covering and shield shall be a nonglare surface. Foreign Substance on the ball/Items on pitcher: The pitcher shall not at any time be allowed to use any moisture or foreign substance on the ball, the pitching hand or fingers nor do anything to deface the ball. Neither shall any other player or team personnel apply moisture or a foreign substance to the ball nor do anything to deface the ball. Under the supervision and control of the Umpire, powdered resin may be on the hands to dry them. Gorilla Gold is a type of resin and is allow by USSSA Fast Pitch. The pitcher?s fingers, hand, wrist, forearm or elbow may be taped for injury, providing such tape is a neutral color.
NSA: During the game, the pitcher may not use tape or other substances on the ball, pitching hand or fingers; nor shall any player apply any foreign substance to the ball. With the umpire?s approval, powdered resin may be used to dry the hand. The wearing of any item on the pitching hand, wrist, or arm that may be distracting to the batter will not be allowed.
You can see that each sanctioning body has their own take on these rules.
NFHS prohibits tape on the hand at the "contact points" of the ball. If worn on the hand, but not at a "contact point", then the tape is at the umpire's judgment as to whether it's distracting or not.
ASA doesn't mention tape at all. ANY item worn on the pitching hand is subject to umpire judgment for being distracting.
USSSA allows tape if used due to injury. The tape must be a "neutral color".
NSA prohibits tape on the pitching hand- period.