Back in the early 2000s, I heard about new music from watching Hey Hey Hey Music Champ. They would always have countdowns of top songs that week. Music Station does it too.
Recently I've just been on youtube looking up bands I like and checking the side bar and randomly clicking bands I've never heard of with results being a tremendous success.
Awesome City Club, Oral Cigarettes, Frederic, and Gesu no Kiwami Otome just to name a few of the bands I've gotten into recently.
4 bands I love! Good picks
Saw Frederic and THE ORAL CIGARETTES live in Tokyo this summer, it was a blast.
Here, have some more
KANA-BOON
the HIATUS
Kyuso Nekokami
KEYTALK
ELLEGARDEN
ONE OK ROCK
MONOEYES
Mrs. GREEN APPLE
Straightener
Nothing's Carved In Stone
9mm Parabellum Bullet
The Mirraz
Hitorie
ART-SCHOOL
androp
RADWIMPS
[Alexandros]
SAKANAMON
cinema staff
CreepHyp
Sakanaction
indigo la End
Yonezu Kenshi
Czecho No Republic
04 Limited Sazabys
Arukara
Galileo Galilei
My Hair is Bad
Kuso Iinkai
LAMP IN TERREN
BIGMAMA
Good Morning America
UNISON SQUARE GARDEN
go!go!vanillas
WANIMA
SHIT HAPPENING
Kankaku Piero
Brian the Sun
September Me
Giraffepot
PELICAN FANCLUB
Yoru no Honki Dance
GOOD ON THE REEL
Dramatic Alaska
Kidori Kidori
BLUE ENCOUNT
Contemporary na Seikatsu
All these + the four you mentioned are basically the artists I listen to the most right now.