NeoGAF member, Neoxon, has compiled a huge list of videos that make up the entire Mario Kart 8 soundtrack and posted it to NeoGAF.  The entire set of videos can be viewed below. Enjoy!

Mario Kart 8 Main Theme

https://www.youtube.com/watch?v=YynzwX3PdU4

Mario Kart 8 Online Waiting Room

Rainbow Road 64

Bowser’s Castle

Piranha Plant Slide

Tick Tock Clock

Rainbow Road

Bone Dry Dunes

Moo Moo Meadows

Mount Wario

Mario Kart Stadium

Mario Circuit GBA

Toad Harbor

Dry Dry Desert

Yoshi Valley

Royal Raceway

Sherbet Land

Toad’s Turnpike

Dolphin Shoals

Cheep Cheep Beach

Sunshine Airport

Donut Plains 3

Shy Guy Falls

Mario Circuit

Thwomp Ruins

Sweet Sweet Canyon

Water Park

https://www.youtube.com/watch?v=eZRS3AkIi18

Grumble Volcano

https://www.youtube.com/watch?v=l56LL9a2XTk

Music Park

DK Jungle

https://www.youtube.com/watch?v=wyUZYjm5ex0

Cloudtop Cruise

Twisted Mansion

Electrodome