boko boko = (ground breaking) byuuuu = (wind blowing) doka doka = (kick kick) fugo fugo = (hm hm) fulu fulu = (tremble tremble) and many other in this link http://www.xamuel.com/examples-of-japanese-onomatopoeia/

I am gonna attach a scary story telling presented by Junji Inagawa who is famous for scary story teller in Japan . http://www.youtube.com/watch?v=7K0BT5VVoPo&feature=related Count how many onomatopoeia did he use, if you are ok with scary story! ( His speaking is fast, and sometimes you might be difficult to understand, but enjoy how he use onomatopoedia and how does use action regarding to it.) Enjoy,or ready to be scared, maybe? lol

You can check this question, too. http://www.italki.com/answers/question/79236.htm

わんわん　woof woof,　コケコッコー cock-a-doodle-doo, ズルズル、シュルシュル、ニョロニョロ slithering, チカチカ flickering, フワフワ　fluffy... There are so many!

one of my favorite ones is ザーザー :D it's the sound of heavy rain :D