I'm working on writing up everything in here in far more useful text form. So far I've finished the first three rows of stages. It's mostly self-explanatory (Remix-Old means it was in a previous smash game, mostly Brawl), but I will point out that last track on Mario Galaxy is from Bowser's Inside Story which, if it's the track I think it is, is a really awesome inclusion:
Battlefield:
Battlefield
Multi-Man Smash
Trophy Rush
Menu (Melee) [Remix-Old]
Boss Battle (Melee) [Remix-Old]
Battlefield (Brawl) [Original]
Boss Battle Song 1 (Brawl) [Original]
Menu
Big Battlefield:
Battlefield
Multi-Man Smash
Trophy Rush
Menu (Melee) [Remix-Old]
Boss Battle (Melee) [Remix-Old]
Battlefield (Brawl) [Original]
Boss Battle Song 1 (Brawl) [Original]
Menu
Final Destination:
Final Destination
Final Destination Ver. 2
Master Hand
Menu (Melee): Ver. 2 [Remix]
Credits (Super Smash Bros.) [Remix-Old]
Final Destination (Brawl) [Original]
Boss Battle Sonc 2 (Brawl) [Original]
Mushroom Kingdom U:
Ground Theme / Underground Theme [Remix]
Super Mario Bros. Medley [Remix]
Super Mairo Bros.: The Lost Levels Medley [Remix]
Fortress Boss (Super Mario World) [Remix]
Athletic Theme / Ground Theme [Remix]
Ground Theme (Super Mario Bros.) [Remix-Old]
Ground Theme (New Super Mario Bros. U) [Original]
Ground Theme (New Super Mario Bros. 2) [Original]
Super Bell Hill [Original]
Mario Galaxy:
Egg Planet [Remix]
Super Mario Galaxy [Original]
Egg Planet [Original]
Theme of SMG2 [Original]
Sky Station [Original]
Fated Battle [Original]
The Great Tower Showdown 2 [Original]
Champion Road [Original]
The Grand Finale [Original]
Delfino Plaza:
Delfino Plaza [Original]
Ricco Harbor [Original]
Super Mario 3D Land Theme / Beach Theme [Remix]
Princess Peach's Castle [Remix-Old]
Rainbow Cruise [Remix-Old]
Main Theme (New Super Mario Bros.) [Remix-Old]
Mario Circuit:
Circuit (Mario Kart 7) [Remix]
Rainbow Road Medley [Remix]
Cloudtop Cruise [Remix]
Mario Circuit (Mario Kart 8) [Original]
Mario Kart Stadium [Original]
Rainbow Road (Mario Kart 8) [Original]
Mushroom Gorge [Original]
Minigame Theme (Mario Party 9) [Original]
Mario Circuit (Brawl):
Mario Circuit [Remix-Old]
Luigi Raceway [Remix-Old]
Waluigi Pinball [Remix-Old]
Mario Tennis / Mario Golf [Remix-Old]
Rainbow Road (Mario Kart: Double Dash!!) [Original]
Title (3D Hot Rally) [Remix-Old]
Excite Truck [Original]
Luigi's Mansion:
Luigi's Mansion Theme [Remix-Old]
Luigi's Mansion Series Medley [Remix]
Airship Theme (Super Mario Bros. 3) [Remix-Old]
Castle / Boss Fortress (Super Mario World/SMB 3) [Remix]
On the Hunt -Glomy Manor Ver.-(Instrumental) [Original]
Tetris: Type A [Remix-Old]
Jungle Hijinxs:
Gear Getaway [Remix]
Jungle Level [Remix-Old]
Jungle Level Jazz Style [Remix]
Stickerbrush Symphony [Remix-Old]
Jungle Hijinxs [Original]
Mole Patrol [Original]
Battle for Storm Hill [Original]
Mangrove Cove [Original]
Swinger Flinger [Original]
Skyloft:
Ballad of the Goddess / Ghirahim's Theme [Remix]
Main Theme / Underworld Theme [Remix]
Saria's Song / Middle Boss Battle [Remix]
The Great Sea / Menu Select [Remix]
Tal Tal Heights [Remix-Old]
Village of the Blue Maiden [Original]
Ballad of the Goddess [Original]
Lorule Main Theme [Original]
Bridge of Eldin:
Main Theme Ver. 2(The Legend of Zelda) [Remix-Old]
Dark World / Dark World Dungeon [Remix]
Title (The Legend of Zelda) [Remix-Old]
Hidden Mountain & Forest [Remix-Old]
Ocarina of Time Medley [Remix-Old]
Hyrule Field Theme [Remix-Old]
Main Theme (Twilight Princess) [Original]
Midna's Lament [Original]
Temple:
Great Temple / Temple [Remix-Old]
Temple Theme [Remix-Old]
Main Theme (The Legend of Zelda) [Remix-Old]
Song of Storms [Remix-Old]
The Dark World [Remix-Old]
Gerudo Valley [Original]
Yuga Battle (Hyrule Castle) [Original]
Pyrosphere:
Vs. Ridley [Remix-Old]
Title (Metroid) [Remix]
Escape [Remix]
Sector 1 [Remix-Old]
Vs. Meta Ridley [Original]
Multiplayer (Metroid Prime 2: Echoes) [Original]
Nemesis Ridley [Original]
Norfair:
Main Theme (Metroid) [Remix-Old]
Brinstar [Remix-Old]
Brinstar Depths [Remix-Old]
Norfair [Remix-Old]
Ending (Metroid) [Remix-Old]
Theme of Samus Aran, Space Warrior [Remix-Old]
The Burning Lava Fish [Original]
Battle Scene / Final Boss (Golden Sun) [Remix-Old]
Port Town Aero Dive:
Mute City Ver.3 [Remix]
Mute City [Remix-Old]
White Land [Remix-Old]
Fire Field [Remix-Old]
Big Blue [Remix-Old]
Mute City [Original]
Red Canyon [Original]
Dream Chaser [Original]
Devil's Call in Your Heart [Original]
Climb Up! Angd Get the Last Chance! [Original]
Brain Cleaner [Original]
Shotgun Kiss [Original]
Planet Colors [Original]
Woolly World:
Yoshi's Island [Remix]
Yoshi's Woolly World [Remix]
Obstacle Course (Yoshi's Island) [Remix-Old]
Yoshi's Story Ver.2 [Remix-Old]
Ending (Yoshi's Story) [Remix-Old]
Wildlands [Remix-Old]
Main Theme (Yoshi's New Island) [Original]
Bandit Valley (Yoshi's New Island) [Original]
Yoshi's Woolly World [Original]
Try, Try Again [Remix]
Tough Guy Alert! [Original]
Yoshi's Island:
Super Mario World Medley [Remix]
Ground Theme (Super Mario Bros. 3) [Remix-Old]
Yoshi's Island (Melee) [Remix-Old]
Yoshi's Story [Remix-Old]
The Great Cave Offensive:
The Great Cave Offensive [Remix]
Butter Building Ver.2 [Remix]
King Dedede's Theme Ver. 2 [Remix]
Forest/Nature Area [Remix]
Green Greens Ver. 2 [Remix]
Green Greens (Melee) [Remix-Old]
Celestial Valley [Original]
The Adventure Begins [Original]
Through the Forest [Original]
Floral Fields [Original]
Halberd:
The Legendary Air Ride Machine [Remix-Old]
Gourmet Race [Remix-Old]
Meta Knight's Revenge [Remix-Old]
02 Battle [Remix-Old]
Boss Theme Medley [Remix-Old]
Orbital Gate Assault:
Theme from Area 6 / Missile Slipstream [Remix]
Star Wolf's Theme / Sector Z [Remix]
Corneria [Remix-Old]
Main Theme (Star Fox 64) [Remix-Old]
Area 6 [Remix-Old]
Space Battleground [Original]
Break: Through the Ice [Original]
Lylat Cruise:
Space Armada [Remix-Old]
Main Theme (Star Fox) [Remix-Old]
Corneria (Brawl) [Remix-Old]
Venom [Remix-Old]
Star Wolf [Remix-Old]
Tunnel Scene (X) [Remix-Old]
Kalos Pokemon League:
Battle! (Trainer Battle) (Pokemon X / Pokemon Y) [Remix]
Battle! (Champion) / Champion Cynthia [Remix]
Route 10 [Remix]
N's Castle Medley [Remix]
Route 23 [Remix]
Battle! (Team Flare) [Remix]
Pokemon Center (Pokemon Red / Pokemon Blue) [Remix-Old]
Battle! (Team Galactic) [Remix-Old]
Battle! (Dialga/Palkia) / Spear Pillar [Remix-Old]
Victory Road (Pokemon X / Pokemon Y) [Original]
Battle! (Champion) (Pokemon X / Pokemon Y) [Original]
Onett:
Onett [Remix-Old]
Magicant / Eight Melodies (Mother) [Remix]
Onett Theme / Winters Theme [Remix]
Smiles and Tears [Remix]
Pollyanna (I Believe in You) [Remix-Old]
Snowman [Remix-Old]
Mother 3 Love Theme [Remix-Old]
Porky's Theme [Remix-Old]
Coliseum:
The Devoted [Original]
Coliseum Series Medley [Remix]
Fight 1 (Fire Emblem Gaiden) [Remix]
Meeting Theme Series Medley [Remix]
Fire Emblem: Mystery of the Emblem Medley [Remix]
Time of Action [Original]
Id (Purpose) [Original]
Duty (Ablaze) [Original]
Attack (Soma Bringer) [Original]
Castle Siege:
Fire Emblem theme [Remix-Old]
Fire Emblem [Remix-Old]
Shadow Dragon Medley [Remix-Old]
With Mila's Divine Protection (Celica Map 1) [Remix-Old]
Attack (Fire Emblem) [Remix-Old]
Preparing to Advance [Remix-Old]
Crimean Army Sortie [Original]
Against the Dark Knight [Original]
Victory Is Near [Original]
Palutena's Temple:
Boss Fight 1 (Kid Icarus: Uprising) [Original]
Wrath of the Reset Bomb [Remix]
Lightning Chariot Base [Remix]
Destroyed Skyworld [Remix]
Magnus's Theme [Original]
Dark Pit's Theme [Original]
Hades's Infernal Theme [Original]
Thunder Cloud Temple [Original]
Skyworld:
Underworld [Remix-Old]
Title (Kid Icarus) [Remix-Old]
Overworld [Remix-Old]
Kid Icarus Retro Medley [Original]
Gamer:
Gamer [Original]
Ashley's Song (JP) [Remix-Old]
Ashley's Song [Remix-Old]
WarioWare, Inc. [Remix-Old]
WarioWare, Inc. Medley [Remix-Old]
PERFORMANCE [Original]
Dragon Battle [Original]
Garden of Hope:
Stage Select (Pikmin 2) [Remix]
Stage Clear / Title (Pikmin) [Remix-Old]
Environmental Noises [Remix-Old]
World Map (Pikmin 2) [Remix-Old]
Main Theme (Pikmin) [Original]
Garden of Hope [Original]
Town and City:
Plaza / Title (Animal Crossing: City Folk / Animal Crossing: Wild World) [Remix]
Tour [Remix]
Kapp'n's Song [Remix]
Outdoors at 7 p.m. (Sunny) / Main Street [Remix]
Bubblegum K.K. [Remix]
Wii Fit Studio:
Super Hoop [Remix]
Skateboard Arena (Free Mode) [Remix]
Rhythm Boxing [Original]
Mischievous Mole-way [Original]
Bathtime Theme [Remix]
Bathtime Theme (Vocal Mix) [Remix]
Brain Age: Train Your Brain in Minutes a Day! [Original]
Menu (Brain Age 2: More Training in Minutes a Day!) [Original]
Boxing Ring:
Jogging/Countdown [Remix]
Minor Circuit [Remix]
World Circuit Theme [Original]
Culdcept [Remix]
Shin Onigashima Medley [Remix-Old]
Tomorrow's Passion [Original]
Gaur Plain:
Gaur Plain [Original]
Xenoblade Chronicles Medley [Remix]
Engage the Enemy [Original]
Gaur Plain (Night) [Original]
Time to Fight! [Original]
An Obstacle in Our Path [Original]
Mechanical Rhythm [Original]
You Will Know Our Names [Original]
75m:
Donkey Kong [Remix-Old]
Opening (Donkey Kong) [Remix-Old]
Mario Bros. [Remix-Old]
25m Theme [Original]
Chill (Dr. Mario) Ver. 2 [Remix]
Wrecking Crew:
Wrecking Crew Medley [Remix]
Wrecking Crew Retro Medley [Original]
Balloon Fight Medley [Remix]
Ice Climber [Remix-Old]
Stack-Up/Gyromite [Remix-Old]
Mach Rider [Remix-Old]
Lip's Theme (Panel de Pon) [Remix-Old]
Pilotwings:
Light Plance [Remix]
Light Plane (Vocal Mix) [Remix]
Turbo Jet [Remix]
Light Plane [Original]
Dillon's Rolling Western: The Last Ranger [Original]
Wuhu Island:
Wii Sports Series Medley [Remix]
Wii Sports Resort [Remix]
Opening Theme / Select (Wii Sports) [Original]
Style Savvy: Trendsetters [Remix]
Pop Fashion Show [Original]
Windy Hill Zone:
Windy Hill - Zone 1 [Original]
Green Hill Zone [Original]
Angel Island Zone [Remix-Old]
Open Your Heart [Original]
Live & Learn [Original]
Escape from the City [Original]
Sonic Heroes [Original]
Wonder World [Original]
His World (Instrumental) [Original]
Seven Rings in Hand [Original]
Rooftop Run [Original]
Reach for the Stars [Original]
Wily Castle:
Mega Man 2 Medley [Remix]
Cut Man Stage [Remix]
Quick Man Stage [Remix]
Air Man Stage [Remix]
Spark Man Stage [Remix]
Shadow Man Stage [Remix]
Mega Man Retro Medley [Original]
Mega Man 2 Retro Medley [Original]
Mega Man 3 Retro Medley [Original]
Mega Man 4-6 Retro Medley [Original]
Menu:
Menu
Menu (Melee) [Original]
Menu 2 (Melee) [Original]
Menu (Brawl) [Original]
How to Play [Original]
Trophies (Melee) [Original]
Trophy Gallery (Brawl) [Original]
Online Practice Stage (Brawl) [Original]