Other J-Pop Websites?
 

Forgive me if this is not allowed, but I can't seem to find very many.

Does anyone know similar websites like this that have to do with other Japanese artists? Such as GACKT, Daisuke Asakura, HYDE, VAMPS, Namie Amuro, Koda Kumi, T.M.Revolution, Miyavi?

I have a massive list, but maybe share any you have or think of? I'd be forever grateful ^_^

You mean it, forums?
There is stage48 which is a forum for 48G/46G (AKB48 and etc).

Jpopcentral
Onehallyu - This has more kpop, but it has a lot of japanese threads.