A some of the commands here are no longer work, if you want to update it let me know

To open the console use the tilde (~) or just Enter

If the console does not open, do the following:

Press F3 and F8, and uncheck the box for Disable Console

When you load back in to your save after doing the above you just neew to hit F3.

COMMANDS: Displays all commands.

MADLOOT: Gives the player a: a knife,a Builder ,3 Batteries ,4 chips ,10-still 10 glass.

nocost: items have no cost. Thx Brodye

GOTO GENROOM/AURORA: Moves the player in the reactor room at Aurora

nodamage: Gives you god mode

Oxygen: Gives infinite air

NITROGEN: Includes more time under water (i dont know if this works)

WARP: Will move the player according to the coordinates of the selected player

RESTORESHIP: Will restore the ship

FREECAM: Activates free cam

UNLOCKALL: Gives all of the Blueprints

BLUEPRINT NAME: Gives the player the specified blueprint

Examples:

BLUEPRINT SEAMOTHBLUEPRINT

ITEM Titanium 5 *NAME - the name of the object such as Titanium. # - number you would like to spawn.

Note: If the item name contains two words you'll need to write as a single word, such as:
item enameledglass 4

Basic materials

Item Titanium

Item TitaniumIngot

Item Silicone

Item Glass

Item Bleach

Item Magnesium

Item EnameledGlass

Item PlasteelIngot

Advanced materials.

Item Lubricant

Item HydrochloricAcid

Item Bleach

Item Benzene

Item AramidFibers

Item Aerogel

Item Polyaniline

Item Graphene

Electronics.

Item CopperWire

Item Battery

Item PowerCell

Item ComputerChip

Item WiringKit

Item AdvancedWiringKit

Item Nanowires

Materials.

Item Copper

Item Salt

Item Quartz

Item Silver

Item Gold

Item Lithium

Item Diamond

Item ScrapMetal

Item Stalkertooth

Item AcidMushroom

Item CoralChunk - (Coral Sample)

Item JeweledDiskPiece - (Table Coral Sample)

Item KooshChunk

Item TreeMushroomPiece

Item Uranium

Item MercuryOre

Item BloodOil

Item Sulphur

Item AluminumOxide

Item OpalGem

item crashpowder

Item precursorioncrystal

Personal Equipment.

Item SeaGlide

Item Tank

Item Fins

Item RadiationSuit

Item RadiationHelmet

Item RadiationGloves

Item Stillsuit

Item FirstAidKit

Item Fireextinguisher

Item Rebreather

Item Pipe

Item Compass

Item Thermometer

Item DiveSuit

Tools.

Item Constructor

Item Flashlight

Item Knife

Item Divereel

Item Airbladder

Item Flare

Item Builder

Item Welder

Item Lasercutter

Item StasisRifle

Item Terraformer

Item Transfuser

Item Beacon

Transports

Item Seamoth

sub cyclops

Item Exosuit

Upgrades.

Item HullReinforcementModule - (Hull)

Item HullReinforcementModule2 - (Shell)

Item HullReinforcementModule3 - (Chelonian)

Item PowerUpgradeModule -

Item SeamothReinforcementModule - (Seamoth Pressure Compensator)

Item SeamothPowerUpgradeModule - (Seamoth Power Efficiency Module)

Item SeamothSolarCharge - (Seamoth Solar Charger)

Item SeamothStorageModule - (Seamoth Storage Solution)

Item SeamothElectricalDefense - (Seamoth Perimeter Defense System)

Item SeamothTorpedoModule - (Seamoth Torpedo System)

Item SeamothSonarModule - (Seamoth Sonar)

Item SeamothArmorPlating - (Seamoth Hull Reinforcement)

Blueprints.

Item SeamothBlueprint

Item SpecimenAnalyzerBlueprint

Item CyclopsBlueprint

Item FabricatorBlueprint

Item FragmentAnalyzerBlueprint

Item WorkBenchBlueprint

Item ExoSuitBlueprint

Item StasisRifleBlueprint

Item TerraformerBlueprint

Item TransfuserBlueprint

Item PropulsionCannonBlueprint

Food and water.

Item FilteredWater

Item DisinfectedWater

Item StillsuitWater

Cooked food.

Item CookedSpadefish

Item CookedBladderfish

Item CookedBoomerang

Item CookedEyeye

Item CookedGarryfish

Item CookedHolefish

Item CookedHoverfish

Item CookedOculus

Item CookedPeeper

Item CookedReginald

Item CookedHoopfish

Cured food.

Item CuredSpadefish

Item CuredBladderfish

Item CuredBoomerang

Item CuredEyeye

Item CuredGarryfish

Item CuredHolefish

Item CuredHoverfish

Item CuredOculus

Item CuredPeeper

Item CuredReginald

Item CuredHoopfish

Fragments.

Item ExosuitFragment - Fragment "Eczecstwa"

Item ReinforceHullFragment - Fragment "pressure Compensator Cyclops"

Item SeamothFragment - Fragment "Moth"

Item StasisRifleFragment - Fragment "Stasis rifle"

Item TerraformerFragment - Fragment "Terraformer"

Item TransfuserFragment (SO) - Fragment "DNA-Transmitter"

Item WorkBenchFragment - Fragment "Workbench"

Item PropulsionCannonFragment - Fragment "Gravity-gun"

Item ThermalPlantFragment - Fragment "Thermal power plant"

Item NuclearReactorFragment - Fragment "Nuclear reactor"

Item MoonPoolFragment - Fragment of "Connecting shaft"

Biomes
BIOME name [Teleports the player to a specific biome]

Biome safe

Biome kelp

Biome grassy

Biome mushroom

Biome koosh

Biome jellyshroom

Biome sparsereef

Biome grandreef

Biome dunes

Biome mountains

Biome deepgrand

Biome bloodkelp

Biome underislands

Biome smokers

Biome inactivelavart

Biome islands

Biome tree

Misc.

Item CurrentGenerator

Item Gravsphere

type day or night it will instantly switch to either respectively.

type survival, freedom or any gamemode to change (THX DaSpyCrabKing)

If i've missed something just tell me in the comments below.
And dont to forget to like and fave
When in doubt Wikipedia
Subnautica Wiki [subnautica.wikia.com]

For some people and myself you cant see what your typeing so try copying this command
Item Flashlight then go in to your game and open a save, next open your consle and hit ctrl v if you get a flashlight you have the bug i have if not try asking for help on the forums.