(BIG FAT NOTE: I'll include here some Hacks ROMS in progress or demo, but it's for that you can give it's a try!)
1.- Jumps Series Hacks (Jump, Jump 1/2, including here YUMP & YUMP 2).
2.- Super Mario World Yeah!
3.- VIP Series Hacks.
4.- Brutal Mario. (There are numerous amount of demos of this, but the last Carol demo was submitted in 2015).
5.- The Devious Four Chronicles Series Hacks.
6.- Super Mario World: The Second Reality Project Series Hacks (including remake).
7.- Mario Is Missing! Done Right!
8.- New Super Mario World Series Hacks (The Twelve Magic Orbs, Around The World and... Including The Twelve Magic Orbs Powered-Up!)
9.- Super Mario 2D Land.
10.- Alex No Super Mario Bros Series Hacks (The Invaders of the Mushroom Kingdom & Mega Mario X).
11.- Super Mario Bros: Peach's Adventure.
12.- Super Mario World Random Revolution First Blood (actually only 2 demos).
13.- VLDC - Vanilla Level Desing Contest Series Hacks.
14.- A Plumber For All Seasons.
16.- A Super Mario Thing.
17.- stick mice in my head and then beat my head in with a hammer and let them back out.
18.- 🐭 So 2 Mice Walk Into a Bar... 🐭
19.- SMW: A Super Mario Adventure Series Hacks.
20.- SMW: Luigi is Villain (phase demo lol).
21.- Mario: The Mystical Gem.
22.- A SMW Central Production 1 & 2.
23.- I HATE YOU.
24.- 'the (in others termines... "The Coronation Day").
25.- GAME (the best name for a creepy Hack ROM...).
26.- Mario & Yoshi Strange Quest (Mario's Strange Quest & Yoshi Strange Quest)
27.- The 3 Little Princesses (actually this are in phase demo)
28.- Mario and Friends in: The Ghost's Gallery.
29.- Super Mario World Odyssey.
30.- Super Mario World: The Secret Of The 7 Golden Statues.
For those wanting a Kaizo in this list, I poorly played some Hacks with it's difficult, but here I leave 5 of them:
2.- The Darkside Series Hacks (including remake).
3.- Item Abuse (don't play this, a hell of all-type carryables sprites are waiting here...)
5.- Super 'Sonic Saves the World'.
These are all that I thought that are... A really amazing work made by the community of SMW Hackers! I hope that this achieved give your list of SMW Hacks ROMS that your will need to play for enjoy the full-power of Super Mario World (this was a piece of cake to compile this wall of text for these that are searching goods Hacks ROMS) Have a nice day!