Cut Halo: The Master Chief Collection customization

Throughout its history, Halo: The Master Chief Collection has seen a huge variety of player customization options. Many of these options have been removed from the game in subsequent updates, though several have never been useable.

Unreleased Armor
Armor that has been added and removed from The Master Chief Collection at various points, though never officially released.

Preserve
One of several pieces of equipment cut from the original release of the Anniversary Map Pack for Halo: Reach in 2011, the "Preserve" chest can be found in the files of the collection, fully-textured. Unlike its siblings in the EXO/TSCS chest and AKIS & Mariner helmets, this chest has yet to be implemented for use as an armor permutation.

Operator
One of many cut Halo Online armor sets intended to be included in Halo 3, this set's icons were included in the flight files for Season 7, though it ultimately has yet to be released. This set can be seen in the Season 5 Trailer.

Spectrum
Another cut Halo Online armor set intended to be included in Halo 3, this set's icons were included in the flight files for Season 7, though it ultimately has yet to be released. This set can be seen in the Season 5 Trailer.

Defender
Named "Utility" in the files, the icons for this Halo Online iteration of the DEFENDER-class Mjolnir were included in the flight files for Season 7, though it was ultimately never released.

Extractor
Another cut Halo Online armor set intended to be included in Halo 3, this set's icons were included in the flight files for Season 7, though it was ultimately never released.

Knight
Another cut Halo Online armor set intended to be included in Halo 3, this set's icons were included in the flight files for Season 7, though it was ultimately never released.

Blaster
Another cut Halo Online armor set intended to be included in Halo 3, this set's icons were included in the flight files for Season 7, though it was ultimately never released.

Strider
One of many armor sets created for the now-cancelled Halo Online, the Strider armor appeared briefly in the game files for Series 5: Anvil, though has since seemingly been removed.

Removed Armor
Armor that has been changed or removed from The Master Chief Collection at various points.

Blackguard Tearful Bishop
"The faith of the newly converted burns bright enough to consume any truth."

The Tearful Bishop helmet was available as part of the flighting test for Series 8: Mythic, though was cut from the final release for unknown reasons. The helmet would have been available as part of the Blackguard series of Fractures armor for Halo 3 and Halo: Reach. The helmet would be re-added into the MCC in the November 3 update, but the name was changed to "Blackguard Fallen Equerry", and the cross-shape visor and description were altered.

Belos Valorous
In the original flights for Season 8, the Valorous shoulder piece for the Belos Fracture set featured a large V symbol. In the final release, this was changed to the Season 8 lion emblem, for unknown reasons.

Evalach's Lament
With the release of Season 8, the Evalach's Lament back accessory was altered for unknown reasons. During the flight, it was painted with a cross, while the final version was changed to be four squares.

Sword and Board back accessory
Featured in the release of Series 6: Raven, the Sword and Board back accessory in the Season 6 Flight originally was blue and provided two Machetes on the shield, while in the final game it changes color depending on the player's primary color, and features one Machete rather than two.

Azure Techsuit
Introduced with the release of Series 6: Raven, the Azure techsuit used a bright teal coloration during the Season 6 flight. In the final release, this would be changed to a more deep blue.

Rhine
Named the "Rhino" armor in the files, this Halo Online armor set was changed prior to its release in Series 6: Raven as shown by its unused icon images, which display it having no gold, no forearms and different shoulders. This also could mean that Rhine was originally unlockable via the Season 6 Pass.

Skins
The following skins for Combat Evolved have been made unavailable for use.

Unreleased
Skins with the following filenames were shown as icons in the files of the collection for a time when Season 2: Spark launched, though have since been removed. All resembled pink placeholder textures.

Removed
Two skins for the Halo: Combat Evolved Warthogs, both referencing Jurassic Park, were later removed from the game in the Series 5: Anvil update for unknown reasons. The skins were replaced with the Park Ranger and Field Medic skins, respectively.

Nameplates
The following nameplates were changed or removed from The Master Chief Collection at various points, or were never available to use.