Since you like B'z, I'd like to recommend giving Koshi's solo music a try!

My favorite albums are Shian and Hadou!

Oh and I also like to recommend Porno Graffitti. They make some AMAZING music and it's incredibly catchy too! <3
I'm gonna throw these artists in. (Warning! It's long! lol):
Spoiler:
AYUSE KOZUE
BRIGHT
BREAKERZ (Their albums FIGHTERZ and GO are worth listening to!

)
cossami
Every Little Thing
doa
day after tomorrow
mini
Ms.OOJA
NEGOTO
SCANDAL
T.M.Revolution
YU-A
ZARD
Zwei
Natsuiro
Aya Kamaki
Akina Nakamori
Rina Sumioka
Kii Kitano
Kazusa
Yuu Shirota
Maki Ohguro
Masami Okui
Nao Yasuda
Leo Ieiri
Aoi Yamazaki
Jun Shibata
Erica Hashimoto
Nanase Aikawa
Yuka Masaki (her first album is worth listening! <3)
Nana Tanimura
Aoi Eir
Meisa Kuroki
Tomiko Van (Since you listen to DAI...)