Solution:
Any kind of custom resolution that's below 1920x1200 can be added in the "3dsetup.ini".
The ini file is located in "%:\Fifa World Cup 2002\3DSetup"
1] Open the 3dsetup.ini file with any text editor
2] In the 3rd line which starts with "CARD_ALL /C:16 /TB:0 ..", you can see a list of resolutions.
3] Change the resolutions to whatever you desire [As long as it's below 1920x1200]
CARD_ALL /C:16 /TB:0 /R:640x360 /R:640x400 /R:640x480 /R:720x450 /R:720x480 /R:800x480 /R:840x360 /R:854x480 /R:800x600 /R:1024x576 /R:1024x600 /R:1024x768 /R:1000x800 /R:1280x548 /R:1280x720 /R:1280x768 /R:1280x800 /R:1280x1024 /R:1440x900 /R:1600x900 /R:1920x1080 /R:1920x1200
4] Save the .ini file and select the custom resolution from "3DSetup.exe".
Known Issues:
Setting a resolution below 640x360 crashes the game which is cause by texture size of various objects [Example: Kits] to reach above the resolution's limit.
In 640x360, you can't exit the game since confirmation option for closing the game goes below the screen. You have to press "CTRL+ALT+Delete" and close it via task manager.
The main menu is always set to "640x480". Resolutions other than 640x480 will work only after a match starts.
If 640x480 doesn't work, then you need to add 640x480 as custom resolution. Or you can set "WINDOWED=0" in soccer.ini which is located in the game's root folder.
^But then you're stuck with 640x480, no matter what resolution you set in 3dsetup. Neither does any fullscreenizer tool work.
Tested Resolutions:
A lot of the resolutions I've tested aren't available in the "Tested Resolutions & Configurations" menu. So it's fair to note them here:
16:9 resolutions:
640x360
854x480
1024x576
1280x720
1366x768
16:10 resolutions:
640x400
1024x640
1280x800
1440x900
5:3 resolutions:
800x480
1280x768
Other resolutions:
720x480
1024x600