Nip music is really fucking great man. I ended up with a gigantic collection of really, really awesome stuff over the past years and now my music player has about 150 gigs of it permanently available. It actually makes up 99% of what I listen to anymore, now that I think about it. I guess somewhere along the way I turned into a giant weebshit.
The older jazz, funk and city-pop from the 70's up to the 90's is what really cranks my handle after being indoctrinated by vaporwave. It's concentrated dreamy Japanese nostalgia injected straight into your dome.
A lot of great artists, old and new, can be discovered simply by listening to the stuff on jewtube and going through recommendations. Then find it on soulseek. Soulseek very rarely lets me down and I usually find everything except the most obscure artists. Even if it takes a few tries sometimes.
I listen to jpopsuki radio a lot too to discover new jpop artists and I've gotten a lot of my music from there as well. It would be ideal to actually have an account on jpopsuki but since it's a private tracker, their radio + soulseek will tend to your needs in its place. http://jpopsuki.fm/
https://chiru.no/ also has a good station.
For actual animu and game audio you can pretty much find it all on nyaa. Just make sure to try searching by the show's Japanese title if you're not getting many or any results with the english/romaji.
Other anons also gave good advice.
Enjoy!