1 Alola Pokemon League (Pokemon)
I love the Pokemon Arenas in Smash. - HeavyDonkeyKong
2 Ultra Space (Pokemon)
You could travel between dimensions to various different unique locations, maybe with legendaries as part of the areas. While traveling between the dimensions you could fight on a platform. - HeavyDonkeyKong
3 Hyrule Castle (The Legend Of Zelda: Breath Of The Wild)
Maybe sort of like the Temple from Melee. - HeavyDonkeyKong
4 Poke Floats 2 (Pokemon)
I loved the one from Melee! - HeavyDonkeyKong
5 Bowser's Castle (Super Mario Odyssey)
I loved the unique theme of this one. - HeavyDonkeyKong
6 Divine Beast Vah Medoh (The Legend Of Zelda: Breath Of The Wild)
Maybe you could have the fight be on top of Vah Medoh. - HeavyDonkeyKong
7 Studiopolis (Sonic Mania)
One of my favorite levels of the game. - HeavyDonkeyKong
8 Bubblaine/Seaside Kingdom (Super Mario Odyssey)
One of my favorite Kingdoms from the game. - HeavyDonkeyKong
9 Rogueport (Paper Mario The Thousand Year Door)
I loved this hub world. - HeavyDonkeyKong
10 Subspace (Super Smash Bros. Brawl)
A playable stage based on the level. - HeavyDonkeyKong
The Contenders
11 Overgrown Brinstar (Super Metroid)
#1 please - xandermartin98
12 The City (Sonic Forces)
13 Megalovania (Undertale)
AHEM...it's called Last Corridor - xandermartin98
14 Bowser In The Sky (Super Mario 64)
15 Fire Temple (The Legend of Zelda: Ocarina of Time)
16 Slateport City (Pokemon Ruby/Sapphire/Emerald)
17 Twoson (Earthbound)
18 N.Sanity Jungle (Crash Bandicoot)
19 Spiral Mountain (Banjo - Kazooie)
20 Toad Town (Mario and Luigi: Bowser's Inside Story)
21 New Donk City (Super Mario Odyssey)
22 Pallet Town (Pokemon Red and Blue)
23 Outset Island (Zelda Wind Waker)
24 Emerald Coast (Sonic Adventure)
25 Security Hall (Sonic Adventure 2)
26 Koopa Beach (Super Mario Kart)
27 Toad's Turnpike (Mario Kart 64)
28 Bianco Hills (Super Mario Sunshine)
29 Lumiose City (Pokemon XY)
Wasn't it already a course in Smash Bros 3DS?
30 Thwomp Ruins (Mario Kart 8)
31 Mii Plaza (Nintendo 3DS)
32 Blue Sphere Stage (Sonic 3 and Knuckles)
33 Gerudo Dungeon (The Legend of Zelda: Ocarina of Time)
34 Twinleaf Town (Pokemon Diamond/Pearl)
35 Big Arms (Sonic 3 and Knuckles)
36 Nowhere Islands (Mother 3)
37 Vah Medoh (The Legend of Zelda: Breath of the Wild)
38 Coconut Mall (Mario Kart Wii)
39 Great Plateau Tower (The Legend of Zelda: Breath of the Wild)
It's been confirmed
40 Castle Lololo (Kirby's Return to Dreamland)
41 The Sword of the Vale (Pokemon The Movie Black Victini and Reshiram/White Victini and Zekrom.)
Yeah, I know, this is one of those more out there choices. But the Pokemon Anime deserves more Smash Respect.
42 Mechonis Field (Xenoblade Chronicles)
43 Sauria (Star Fox)
44 Clock Tower (Castlevania)
45 Stardust Speedway (Sonic CD)
Maybe the stage can switch to future and past forms like in the game
46 Sandopolis Zone (Sonic)
Possibly have the Act 2 pyramid replace the Act 1 part at times, a few badniks here and there, etc.
47 Phendrana Drifts (Metroid Prime)