What do you call a ブザービーター　in baseball? Is it possible to have something similar to a buzzer beater in baseball? What is it called in Japanese? If not, how would you refer to a game-winning action in a sport?

There is no buzzer to beat in baseball.

The closest thing I can think of is , , etc. They refer to a play that scores a winning run in the bottom of the ninth or later inning and thus literally ends the game.

In sports commentary, []{} is often used to refer to a late game-winning action. It could also be used for a game-tying action in games in which a tie is worth something, such as football. For example, an equalizer in the dying minutes of a match would be called . It is like saying an equalizing goal that brings the (otherwise-dead) team back to life.