i consider 陰陽座 (Onmyo-za) and the yellow monkey from before they got back together (latest single especially does not exist) my favorites
what i mean is i know their discography pretty well, definitely sing along when they come on, read interviews, buy their stuff, comfortably familiar with the members’ public lives and their diff eras, make fan stuff, and like to talk about them and encourage other ppl to enjoy them too 
i really like these too:
All of these are bands on the older side 
A few more that I’ve gotten into, maybe during a specific era:
- Sex Machineguns (especially around the time they came to US)
- Thee Michelle Gun Elephant
- The Back Horn
- Tokyo Jihen
- Malice Mizer
- Love Psychedelico
- Head Phones President
- 色々な十字架 (DIVERS † CROIX “Knowledge” 色々な十字架『知識』)
I like JRO because i can click ppls links when they get excited about some music, bless youtube Like the thread that helped me find sexy songs by Buck Tick, or randomly enjoying a Sailing Before the Wind live recording
definitely sing along w/me 