SCANDAL
One Ok Rock
Alice Nine
LM.C
SiM
SID
Maximum the Hormone
The GazettE
Girugamesh
Fear, And Loathing in Las Vegas
D=OUT
ViViD

Yes alot of Visual Kei :3

SCANDAL
One Ok Rock
Orange Range
The Pillows

updated list:
my favorite bands are in red.
Alice Nine (visual kei/ j rock)
Asian Kung-Fu Generation (j rock)
Balzak (J horror punk)
Beat Crusaders (j rock/ electronic)
The Blue Hearts (j punk)
COBRA (j-punk/ oi punk)
The Cro Magnons (j punk)
Egg Brain (j pop-punk)
Eiji Wentz (jrock/ pop)
Ellegarden (j pop punk/ j rock - mostly english, some japanese)
Fear and Loathing in Las Vegas (j rock/ electronic/ screamo)
FLOW (jrock)
Good 4 Nothing (j punk - the sing in mosty english, but some of their songs are in japanese)
GReeeeN (jrock)
Hi-Standard (j pop-punk)
Ikimonogakari (j-rock)
Kazumasa Oda (j-rock/ soul)
Kemuri (J-ska)
Kishidan (j-rock/ pop)
Kubota Toshinobu (j-pop/ funk/ soul)
Kylee (j pop/ rock)
Maximum the Hormone (j rock/ metal/ punk/ pop/ ska/ screamo)
Midnight Pumpkin (j-ska)
Mr. Children (j rock/ folk)
One Ok Rock (j rock)
Nightmare (visual kei/ j rock)
Orange Range (j rock/ pop/ noise music)
The Pillows (jrock/ indie)
ROTTENGRAFFTY (jrock/ screamo/ metal/ rap rock)
Stance Punks (j punk)
Stereopony (jrock)
Tsuru (jrock/ afrock/ funk)
YOHIO (visual kei)
Yum!Yum!ORANGE (j-ska)
10-FEET (jrock)

Stuff that's not exactly jrock kind of stuff:

Spoiler:

Just One Ok Rock ^^

Liv Moon (J-Metal)
Ellegarden and OF COURSE Scandal