phew: "Phew!", said John with relief when he found the watch that he had lost.
ping: Ping, ping, ping the hail stones landed on the old tin roof.
plop: The rock landed in the water with a big plop!
plunk: The aluminium bat gave off a plunk when it hit the baseball.
pop: The cork blew out of the Champange bottle with a loud pop!
purr: The cat's purr was both soothing and comforting to hear at the foot of her bed.