QUESTION: In action scenes, I use the phrases "suddenly" or "all of a sudden" a ridiculous amount of times when describing fast-paced action scenes. What other words or phrases can I use?
If you write the scene correctly, you don't need "suddenly" or any other synonym or phrase. The reader is usually smart enough to know the fighters in a physical battle are moving fast so everything is "suddenly" unless we say otherwise.
The trick is to get into the head of one of the characters and stay there. Let the reader see what the character sees and feel what the character feels.
You don't say,
Suddenly, the other fighter pulled out his knife and jabbed at him.
Sam dodged the other man's fist. The hand that should have been blocking his next blow moved downward toward the man's knife sheath.
A flash of steel.
Throwing himself backward away from the other man's knife, Sam slammed into the ground on his back.
Or, if you are describing a battle of many men, you don't say
Suddenly, a line of cavalry surged over the top of the hill toward them.
On the hill just above the soldiers, the drumming of many horse hooves and the Rebel yell of hundreds of men warned them.
The Yankees spun around as the Confederate cavalry charged toward them.