Here is a list of Japanese onomatopoeia.
Thanks to this website: http://web.mit.edu/anime/www/onomatopoeia.html

achi kochi
here and there

ban ban
plenty

bari bari
the sound of tearing (e.g., paper), also used to describe being very busy.

bara bara
scattered

basa basa
unkempt hair

bashi bashi
the sound of smacking someone on the head

bera bera
chatting, rattling

bichi bichi
flopping, smacking

bishi
the sound of coming to attention, coming together, or getting into the proper order

boin boin
a well-endowed woman

boki boki
cracking a twig or one's knuckles

bo bo
the sound of a fire burning

boko boko
the sound of hitting something (someone) hard.

boro boro
the sound of a large object (like a barrel) rolling; also ragtag, or worn out

bura bura
staggering around

busu busu
the sound of stabbing

butsu butsu
mumbling, whispering

chika chika
flickering light (see pika pika) eyes tired from too much computer or TV

chaku chaku
steadily

choko choko
always moving around, toddling

deko bako
bumpy

doki doki
the sound of a heart beating fast from excitement (at one time Megumi Hayashibara had a radio program called ``Doki Doki Station'')

don don
building up of events, progression of events, little by little

dosun
the sound of something falling with a thud

dosun dosun
the sound of stomping

fusa fusa
a full and attractive head of hair

fuwa fuwa
fluffy, but also cozy, pleasant

gaku gaku
knees shaking in fear

gara gara
almost empty

gari gari
the sound of grinding or scraping

gasa gasa
dry, rough skin the sound of leaves or papers rustling

gata gata
trembling with cold (humans) vibrations

gatsu gatsu
hungrily, voraciously

gaya gaya
crowded

gera gera
loud laughter

gero gero
``ribbit'' --- the sound a frog makes (in Card Captor Sakura a pun on gero gero is applied to Kero-chan's name)

giri giri
just barely, just in time, ``by the skin of one's teeth''

gito gito
being oily

gocha gocha
the state of disorder common to apartments nagging

gohhon
the sound of someone sneezing

goro goro (boro boro/poro poro)
to laze about, the sound of an upset stomach, the loud rumble of lightning or an avalanche

goshi goshi
the sound of washing clothes vigorously by hand

gucha gucha
soft and wet, an awful mess

guru guru
going around and around in circles

guzu guzu
lazily, slowly

guu guu
the sound of snoring; also the sound of stomach rumbles

gyaa gyaa
the sound of a tantrum

hara hara
heart going pit a-pat, nervousness (see doki doki). The sound made when one is swaying, about to faint.

hou bou
here and there (everywhere)

iki iki
vividly

ira ira
the state of being frustrated

iro iro
this and that, variety, variously.

iyo iyo
more and more (at last)

jime jime
clamminess

jiku jiku
oozing

jiro jiro
to stare

kacha kacha/kata kata
the sound of small things clattering

kan kan
very angry

kara kara
very dry

kari kari
the sound of someone scratching their head in puzzlement

kera kera/keta keta
laughter

kira kira
glitter and sparkle

kokekokko
cock-a-doodle-doo

kowa kowa
From kowai, scared. An expression of being scared.

kusu kusu
giggling

kuyo kuyo
worry about, mope, brood

kyoro kyoro
looking around restlessly

mago mago
confused

masu masu
more or less, increasing

mecha mecha
messed up, illogical, unreasonable

meki meki
the state of making rapid progress

mera mera
the sound/state of a fire blazing up

meso meso
sobbing, sniffling

miin miin
cicada

mishi mishi
the sound of creaking

mogu mogu
the sound of eating (perhaps the source of the name of the character Mogglemoggle in Dokkoidar, or at least the source of one of the ways his superior mis-remembers his name).

mori mori
doing something willlingly

moto moto
originally, by nature, from the start

mou mou
the sound a cow makes

muka muka
a sound someone makes when they are disgusted

niko niko
smiling

nita nita
smirking

niya niya
grinning

nyao
the sound a cat makes

pachi pachi
clapping hands

paku paku
eat in big mouth fulls, take big bites

pan pan
pounding (see pon pon); also, a full stomach

pecha kucha
chattering

peko peko
to be very hungry

pera pera
fluent in a language (pera pera appears in a joke in Azumanga Daioh: a foreigner approaches Nyamo-sensei and Yukari-sensei and tries to talk to them. His speech consists solely of "Pera pera" repeated over and over again).

pero pero
licking (e.g., lollipops). Perhaps the origin of the name of the Miyazawa dog in Kare Kano?

pichi pichi
the state of being young, fresh, vigorous

pii pii pii
whining, puling (also used to describe bird-song)

pika pika
glitter, twinkle (spic and span)

piku piku
twitching

piyo piyo
chirping of small birds

pocha pocha
splash in water

poka poka
the state of being nice and warm

pon pon
the sound of drumming. The Takahata film ``Pon Poko'' is named after the sound that tanuki are said to make by drumming on their rotund stomaches.

poro poro (goro goro/boro boro)
the sound of small objects (pebbles, raindrops) rolling down. In the title of Takahata's film Omohide poro poro it is memories that roll down like raindrops.

potsu potsu
the state of small drops falling sporadically

pun pun
A strong smell. Also an expression of anger, like saying "boo, hiss" (or, I suppose, "This stinks!").

raku raku
easily

riin
the sound/state of someone staring

saga saga
the state of being sarcastic

shiku shiku
the sound one makes when crying

tama tama
unexpectedly

teka teka
greasy hair

ten ten
like dots

ton ton (pon pon)
the sound of someone knocking on the door

tsuru tsuru
slippery, smoth

tsuya tsuya
glossy

uro uro
stumble

wai wai
noisy exhuberance

wan wan
the sound a dog makes

zuki zuki
a painful condition