EarthBound Zero has not yet been extensively hacked.
(Note: Locate and add utilities here)
(Note: include some of the history of EB0 here - the hacks needed to get it working) Hacks of EarthBound Zero include Tomato's EB0 remake beta, which features hacking of text, graphics and some ASM.
The enemy, item and PSI data tables have been located.
Lost Levels Online - Spotlight: Earthbound A thorough history of the Earthbound Zero cart.
A file containing a dump and explanation of enemy data
A file containing a dump and explanation of item data
A file containing a dump and explanation of PSI data