Graphics:
Danooodle (Switch Palace expansion)
Green Jerry (edited graphics, ripping the pumpkin in the title screen)
HarvettFox96 (Avant Star font)
Jack Kiketsu (decoration: pumpkins and tombstones)
K3fka (Zombie Koopas)

Music:
Crispy (Here We Go! haunted remix)
FPI (Super Mario Land 2: 6 Golden Coins - Pumpkin Zone)
HertzDevil (Halloween (1978) intro theme)
lolface (Super Mario Maker: Super Mario Bros. - Ghost House)
Masterlink (Romancing SaGa 3 - Leonid's Castle)
MercuryPenny (The Legend of Zelda: A Link to the Past - Dank Dungeons)
MidiGuy (Super Mario All-Stars: Super Mario Bros. - Bonus, Stage Clear, Super Mario All-Stars: Super Mario Bros. 2 - Boss Battle)
Sayuri (Newer Super Mario Bros. Wii - Pumpkin)
Sinc-X (Clock Tower - Laura in the Bathtub (it's sampled, so it's silent in the game over screen))
Zagonia (Here We Go! haunted remix)

Sprites:
dahnamics (Giant Masked Koopa boss)
GreenHammerBro (Giant Masked Koopa boss)
Ladida (Cluster Effects, only rain was used)
mikeyk (Hammer Bro)
Thomas (Sleepy Goomba)

Patches:
Aika (Disable Bonus Stars)
Alcaro (Time Up! fix)
Arujus (No More Sprite Tile Limits)
edit1754 (No More Sprite Tile Limits)
Major Flare (SMB3 Koopas)
imamelia (Disable Bonus Stars)
Lui37 (Minimalist Course Clear)
MathOnNapkins (No More Sprite Tile Limits)
Mattrizzle (SMB3 Koopas)
Tattletale (No More Sprite Tile Limits)
V'Lanta'la'mana'ma'nisha (No More Sprite Tile Limits)
wiiqwertyuiop (Minimalist Course Clear)

Blocks:
Broozer (Bounce Block)

Tools:
Alcaro (Asar)
FuSoYa (Lunar Magic)
JackTheSpades (PIXI)
Kipernal (AddMusicK)
p4plus2 (Gopher Popcorn Stew)
Smallhacker (SMW Status Bar Editor)
TheBiob (Gopher Popcorn Stew)