I need to talk to you.
What about the joke: Knock-knock Who's there? I could tell that the fire truck was somewhere nearby.
Words like pow and ker-plash help drive the action of the story.
Although there are many more examples of onomatopoeic words that failed to make it to the list, familiarizing these examples will get you off to a great start.
Like many forms of onomatopoeia, the more letters we include, the louder or longer a sound will be.