As with many games, Diablo 2 Items was originally intended to be much more

As with many games, Diablo 2 Items was originally intended to be much more expansive than the final product, with a large number of monsters, characters, items, and quests never making it into the retail release.[7] A large portion of this content is still contained on dormant files hidden on the CD of the game.

* Some spells never made it into the final game. The original game was supposed to have six spell-book pages (this can be checked in Diablo's manual, page eighteen, in a screenshot where the spell-book has six pages), unlike the four in the final, and the spells left on the CD are Invisibility (whose icon graphic was reused for the Teleport spell in Diablo 2 Items), Blood Boil, Blood Ritual, Doom Serpents, Etherealize, and Sentinel. Most of these spells are disabled, but some, like Etherealize, can be enabled with the help of hacks, and Doom Serpents' graphics can still be extracted from the game's main data file.[8]

* Some enemies don't appear in the final game, such as the Unraveler (which is now a monster found in Act 2 of Diablo 2 Items), Goat Lord, Incinerator, Bone Demon, Invisible Lord, The Arch Lich Malignus, and Devil Kin Brute. Their images can still be viewed in sprite form (.cl2) in the game's main data file. Several of these monsters later appeared in the expansion, Hellfire.