This page serves to chronicle any significant content that has been removed from Subnautica.
The Accumulator was a machine meant to store power for Seabases. It is unknown why it was cut.
Spawn: spawn/item accumulator
Amino Acid was an unimplemented raw material. It was used to create Graphene.
Spawn: item aminoacid
Botanical Analysis MachineEdit
The Current Generator was a deployable crafted using the Fabricator. The Current Generator took up four slots in the player's Inventory, that meant the player could carry 12 of them if their inventory was cleared first. The Current Generator used no power and could be left on all the time.
Once the device was deployed and activated, it would produce a column-shaped hydro-current from an emitter on its front. This stream could push small and large objects alike, including Lifepod 5 and the Reefback. However the Seamoth and Cyclops were not affected by the Current Generator.
The Current Generator has been scrapped and is no longer available in the game.
The Fragment Analyzer was a Placeable Item that was used to decode Fragments into Blueprints. Only one fragment was needed to research a blueprint however the Fragment Analyzer could research four fragments at a time. The progress of analysis was displayed when the player looked at the Fragment Analyzer. At one point a Fragment Analyzer was pre-installed inside the Lifepod. The functionality of the Fragment Analyzer was given to the Scanner and the fragment system was reworked.
Spawn: spawn fragmentanalyzer (Does not work, only works as storage)
Graphene was a material that was crafted at the Fabricator.
Spawn: item/spawn graphene
Lithium Ion BatteryEdit
The Lithium Ion Battery was an upgrade to the Battery that was crafted at the Modification Station. The Lithium Ion Battery held twice as much energy as the Battery. The Lithium Ion Battery can now only be crafted in Creative Mode. A new battery, the Ion Battery, uses an Ion Crystal instead of Lithium.
Spawn: item lithiumionbattery
Spawn: item nanowires
Magnesium was a material crafted using three Salt Deposits in the Fabricator. Magnesium was only used in one crafting recipe, that of the Repair Tool. As it was only used in one recipe it was seen as useless and was removed, being replaced by salt in its sole crafting recipe.
The Old Observatory was a small primitive glass box that could be constructed with the Mobile Vehicle Bay. Unlike the newer Observatory it was not a Seabase module and was instead freestanding. It had two entrances and was primarily used to observe Fauna and the environment. The only way to move it was to use Floaters.
Old Nuclear ReactorEdit
The old Nuclear Reactor was built outside of the Seabase and had to be supplied with raw Removed Content#Uranium to function.
The Power Generator was a Placeable Item that generated Power for Seabases using Power Cells. The Power Generator had a capacity. In the starting of Subnautica it was the only method to give energy to Seabases, and it didn't need any kind of item to generate the energy.
The Powerglide was an upgrade for the Seaglide, it was 3x the speed of the Seaglide and had a turbo boost that drastically increased the speed of the Powerglide. The Powerglide's model was identical to that of the Seaglide's.
Spawn: item powerglide (model is bugged)
The Terraformer was a tool that allowed the player to remove material from one place in the world and deposit it somewhere else. A counter showed the current amount of material held by the device.
Terraformer's Removal from gameEdit
The Terraformer was removed due to performance issues because of the way the Terraformer works. The Terraformer model may later be used for an unknown purpose in later updates, as the developers thought the model was "too cool". 
Spawn: item terraformer
The Thermometer was a piece of equipment that allowed the player to see the temperature at their current location. It was removed because it was rarely used during gameplay, rendering it useless. The appearance of temperature was moved to vehicle HUDs instead.
Spawn: spawn specimenanalyzer (does not work and only holds small eggs)
Uranium was an item belonging to the Advanced Materials category that was removed in the Prison Update. It was crafted using three Uraninite Crystals, and was used in the crafting of Reactor Rods and several Electronic items. Uranium was removed to simplify the Reactor Rod recipe.
Shell Hull Reinforcement ModuleEdit
The Shell Hull Reinforcement Module was an Upgrade Module for the Cyclops. When used to upgrade the Cyclops, it added 1600 meters to both the safe depth and the crush depth. This item was removed when the new, non-stacking upgrade system was introduced.
Chelonian Hull Reinforcement ModuleEdit
The Chelonian Hull Reinforcement Module was an Upgrade Module for the Cyclops. When used to upgrade the Cyclops, it added 2800 meters to both the safe depth and the crush depth. The Chelonian Hull Reinforcement Module was the strongest reinforcement module. To create the module, blueprints from the Specimen Analyzer were required as Reefback DNA was part of the recipe. This item was removed when the new, non-stacking upgrade system was introduced.
The entity gallery was a series of textureless, white boxes that could be spawned by typing "entgal" into the console. On top of each box an entity from the world of Subnautica could be found. Of the various things found here, the model of the scrapped "Sandworm" creature was perhaps the most notable.
The entity gallery's removal may have been due to the multiple occasions in which Precursor objects were mistakenly added to the gallery; This resulted in Precursor objects and bases being revealed to the public long before they were intended to be. The most well known example of this was the "Rainbow Update" in which many of the games textures were converted to multicoloured squares, this was because the game had gone over the limit of textures by the accidental addition of a work-in-progress Quarantine Enforcement Platform model and several other Precursor props to the gallery.