I'm veeeeeery low on the boygroups part.
Boygroups
- SUPER★DRAGON (not really a fan, but it's what comes closer)
If I were to consider Bursters among them; they'd be no. 1
Girlgroups
- PassCode
- Neo Japonism
- Necronomidol
- Ange☆Reve
- KAQRIYOTERROR
- Zenbukiminoseida
- miscast
- Kolokol
- XTeen
- Q'ulle
You may wonder where is Dreamcatcher. Well, the distance I have putting on them have caused many Japanese groups to beat them. From all of them, miscast is likely to go higher faster than the others. Necronomidol is potentially one that could go up to standom, depending on what they do on they're upcoming comeback; and if that materializes, they'll go second.