Surprised I didn't find these before, but they're awesome:
Arabian Night Remix (by mrbuttercup37):
https://soundcloud.com/mrbuttercup37/an-old-one-wario-land-4
Pinball Zone Remix (nightsparkle):
https://soundcloud.com/nightsparkle/wario-land-4-pinball-zone
And his version 2:
https://soundcloud.com/nightsparkle/wario-land4-pinball-zone-version-two
All I've Gathered Turns into Sand (Bickety Bunt):
https://soundcloud.com/bickety_bunt/all-ive-gathered-turns-into-sand-wario-land-4-credit-intro
Crescent Moon Village Remix (knup):
https://soundcloud.com/retro-bro/wario-land-4-crescent-moon-village-knup-remix
Wario's Terrifying Stopwatch (SchrafftVortex):
https://soundcloud.com/schrafftvortex/warios-terrifying-stopwatch
Mystic Lake Remix (Final Deluxe/Just Cos)
https://soundcloud.com/henrybmusic/false-mystic
Midnight Passage (Golden Passage Beta theme remix by Mr Nice Productions):
https://soundcloud.com/mr-nice-39/wario-land-custom-music-midnight-passage
Toy Block Tower Remix (RatbotnkD's vocal remix):
https://soundcloud.com/radbotnkd/toy-block-drowning-pool
Arabian Night Remix (by mrbuttercup37):
https://soundcloud.com/mrbuttercup37/an-old-one-wario-land-4
Pinball Zone Remix (nightsparkle):
https://soundcloud.com/nightsparkle/wario-land-4-pinball-zone
And his version 2:
https://soundcloud.com/nightsparkle/wario-land4-pinball-zone-version-two
All I've Gathered Turns into Sand (Bickety Bunt):
https://soundcloud.com/bickety_bunt/all-ive-gathered-turns-into-sand-wario-land-4-credit-intro
Crescent Moon Village Remix (knup):
https://soundcloud.com/retro-bro/wario-land-4-crescent-moon-village-knup-remix
Wario's Terrifying Stopwatch (SchrafftVortex):
https://soundcloud.com/schrafftvortex/warios-terrifying-stopwatch
Mystic Lake Remix (Final Deluxe/Just Cos)
https://soundcloud.com/henrybmusic/false-mystic
Midnight Passage (Golden Passage Beta theme remix by Mr Nice Productions):
https://soundcloud.com/mr-nice-39/wario-land-custom-music-midnight-passage
Toy Block Tower Remix (RatbotnkD's vocal remix):
https://soundcloud.com/radbotnkd/toy-block-drowning-pool