For troubleshooting, a clean environment is invaluable. If you're experiencing crashes, you can load the vanilla copy to instantly test if the issue is with the game or caused by your mods. Even if you do want to use some light mods, the golden rule is always to "backup any modified files" before making changes, ensuring you have a quick and easy way to revert to the stable base.
If you are looking for specific files, searching for contributors like AznIronMan on sites like ProWrestlingMods.io is a highly recommended alternative for finding clean assets Are you trying to restore a specific character or are you looking for a full backup of the game's directory? wwe 2k19 vanilla files better