I've compiled others playlists from Splatunes 1,2 & 3, Octotune, Smash Bros & MK8 remixes, and the live performances. Excludes the SFX tracks. Will keep this up to date as more music/lives come out.

Splatoon Music

Splatune | Splatoon ORIGINAL SOUNDTRACK

Lobby

Plaza

High-Color City Tutorial

Visiting High-Color City

Player Make

Sucker Punch

Hooked

Quick Start

Friend List

Battle Lose Result

Battle Lose Jingle

Battle Win Result

Battle Win Jingle

Now or Never!

Metalopod

Kraken Up

Seaskape

Ink or Sink

Splattack! (Jam Session)

Opening

Imagine if Nintendo uploaded all their music to streaming sites, and you didn't have to use soundcloud for it. What a world that would be

Splatoon Music

Nabs