CVars in this category have been removed in a previous patch.

anisotropic - Anisotropic Filtering in video settings, from 1 to 16
CombatDeathLogRange - Defines the range in which players/mobs dying will be recorded in the combat log or not
CombatModeMaxDistance - Range for combat auto target
dbCompress - Database compression (?)
displayFreeBagsSlots - Option to display free slots, now default
DistCull - Sets distance for culling of objects near farclip
doodadAnim - Toggle animated geometry
EmoteSounds - Replaced by Sound EnableEmoteSounds
EnableAmbience - replaced by Sound EnableAmbience
EnableErrorSpeech - Replaced by Sound EnableErrorSpeech
EnableGroupSpeech - Enable voice emotes (?)
EnableMusic - Replaced by Sound EnableMusic
EnableSoundWhenGameIsInBG - Replaced by Sound EnableSoundWhenGameIsInBG
farclipOverride - Resets farclip if past max setting
flatFileSystem - Flatten the on-disk hierarchy (?)
frillDensity - Replaced by groundEffectDensity
frilldistance - Replaced by groundEffectDist
fullAlpha - Enable full alpha on terrain doodads
horizonfarclip - Set draw distance for the horizon.
horizonnearclip - Set draw distance for terrain closest to you.
lod - Level of detail, toggles the level of detail option in the graphics menu
M2ForceAdditiveParticleSort - force all particles to sort as though they were additive
M2OverrideModel - replace one model with another
M2UsePixelShaders - Enable pixel shaders for models
M2UseShaders - Enable vertex shaders for models
mapObjLightLOD -
mapObjOverbright - Enables Color Bleeding for Bright Lights
MapWaterSounds - Enable water sounds
MasterVolume - Replaced by Sound MasterVolume
MusicVolume - Replaced by Sound MusicVolume
occlusion - Disables rendering of objects that are entirely blocked by other graphics
pixelShaders - Enable pixel shaders -probably replaced by ffx
PlayerFadeInRate - fade in rate for player mouseover
PlayerFadeOutAlpha - min fade out alpha for player mouseover
PlayerFadeOutRate - fade out rate for player mouseover
playerTextureLevels - Number of mip levels used for component texture
previewTalents - replaced with previewTalentsOption
questLogCollapseFilter - replaced with questLogCollapseHeaderFilter
realmName - Name of most recently used realm (displayed in the lower right corner) (Removed in 5.4.1) Use GetRealmName instead.
ShowAllSpellRanks - Shows all ranks of all spells
showsmartrects - Deprecated in WoW 3.0
shadowBias - Blob Shadow transparency levels
shadowLevel - Level of detail for shadow mip maps
smallcull - Affects the hiding ('culling') of small objects. Setting to 0 disables.
SoundBufferSize - Sound buffer size
SoundDriver - Sound driver
SoundInitFlags - Initialization flags for sound system (?)
SoundMemoryCache - Sound cache memory size in MB
SoundMixer - Sound mixer to use
SoundMixRate - Sound mix rate
SoundOutputSystem - Sound system
SoundReverb - Enables sound reflections depending on room size
SoundRolloffFactor - Sound rolloff factor (?)
SoundUseHardware - Replaced by Sound EnableHardware
SoundVolume - Sound volume
specular - Enable specular shading
SpellEffectLevel - Increases amount of spell effects
statusBarText - Replaced by several indivual CVars
texLodBias - Texture Level of Detail Bias (?)
triangleStrips - Deprecated in WoW 3.0
Trilinear - Enable trilinear filtering
unitDrawDist - Unit draw distance
UnitNameCompanionName - Toggle Companion Names
UnitNameEnemyCreationName - Toggle Enemy Creation Names
UnitNameFriendlyCreationName - Toggle Friendly Creation Names
waterLOD - Level of Detail for water (Locked)

List of removed CVars up to Patch 8.1.5

AllMPQLocal - Keeps track if the background streaming has downloaded all MPQ files
CinematicJoystick - Enables cinematic joystick control
CombatDamage - Enables floating damage display over enemy targets
CombatHealing - Enables floating healing display over friendly targets
CombatLogPeriodicSpells - Enables periodic spells in combat log (?)
DesktopGamma - Matches Windows' Gamma Settings
EnableMicrophone - Enables the Microphone
EnableVoiceChat - Enables Voice Chat
InboundChatVolume - The volume of all other chat you hear (0.0 - 1.0)
Joystick - Enables Joystick control
M2BatchDoodads - Enables handling of Detail Doodads in batches (combine doodads to reduce batch count)
M2BatchParticles - combine particle emitters to reduce batch count
M2FasterDebug - Enables developer dynamic control (programmer control of scene optimization mode)
M2Faster - End user control of scene optimization mode
M2UseClipPlanes - Use clip planes for sorting transparent objects
M2UseZFill - Enables Z-Fill on transparent objects
MaxLights - Maximum number of hardware lights
MemUsage - Seems to be a console-only command, but displays nothing as of 4.0.3
ObjectFadeZFill - Fade objects using ZFill pass
OutboundChatVolume - The software amplification factor (0.0 - 2.0)
PetMeleeDamage - Show floating pet meelee damage over enemy targets
PetSpellDamage - Show floating pet spell damage over enemy targets
SkySunGlare - Toggles Sun Glare
Sound_EnableHardware - Enables Audio Hardware Acceleration
Sound_EnableMode2 - Enables Alternate sound processing
Sound_EnableSoftwareHRTF - Enables headphone designed sound subsystem
Sound_OutputQuality - Changes the level of Sound Quality (0 - 2)
UIFaster - UI acceleration level
UseAnimKits - Use AnimKits instead of the old unit animation system
WorldPoolUsage - Seems to be a console-only command, but displays nothing as of 4.0.3 (static/dynamic/stream)
accountList - Saves multiple account names for login screen
accountName - Saves 1 account name for login screen
accounttype - Saves what expansion level the user is playing on
advancedWorldMap - Enables advanced World Map features
autoRangedCombat - Automatically switch between ranged and meelee attack
baseMip - Base level for mip mapping ("Texture Resolution" slider)
bgLoadThrottle - Set the maximum percentage of available bandwidth for background streaming
blizzcon - Enables blizzcon special client behavior
bloatnameplates - Increases size of nameplates based on threat percentage
bloattest - Seems to shrink nameplates for any value greater than zero, probably bugged as of 4.0.3
bloatthreat - Makes nameplates larger depending on gaining/losing threat. Only active when a mob has multiple units on its threat table
cameraDistanceMaxFactor - Sets factor by which cameraDistanceMax is multiplied
cameraDistanceMax - Sets the maximum distance which you can zoom out to.
cameraDistanceMoveSpeed - Sets the speed that the camera zooms in and out.
cameraDistanceSmoothSpeed - Sets the speed that the camera zooms in and out. (possible related to camerasmooth)
characterFrameCollapsed - Show detailed stats on the player character frame
combatLogOn - Whether or not the combat log is shown
consolidateBuffs - Enables buff consolidation
conversationMode - Changes the mode of RealID conversations
coresDetected - Number of CPU cores detected
decorateAccountName - Seems like this in only used on korean realms
enableCombatText - Enables floating combat text
environmentDetail - Controls model draw distance for doodads (WoW 3.0)
expansionMovie - Display Burning Crusade intro at startup (This variable is reset to 0 after the video has been shown)
ffxNetherWorld - Enables full screen "nether world" effect, e.g. for a Mage's [Invisibility]
ffxRectangle - Enables Widescreen Framebuffer
ffxSpecial - Enables alternative on screen effects (WoW 3.0 Wrath-Logo-Small.png)
ffx - Enables all pixel shaders
fixedFunction - Force fixed function pixel and vertex processing
guildRecruitmentChannel - Whether to join the Guild Recruitment channel on login
guildRewardsCategory - Show category of guild rewards
gxColorBits - Color bits
gxCursor - Enables hardware cursors
gxDepthBits - Depth bits
gxFixLag - Smooth mouse cursor
gxMultisampleQuality - Quality for anti-aliasing (?)
gxMultisample - Enables anti-aliasing (e.g. "4" for 4x multisampling)
gxRefresh - Refresh rate in Hz
gxResolution - Screen resolution (e.g. "1280x1024")
gxRestart - Restarts the graphics engine
gxTextureCacheSize - Set the cache size
gxTripleBuffer - Enables Triple Buffering
gxVSync - Enables VSync
gxWindow - Windowed mode
heapAllocTracking - Enables/disables allocation tracking & dumping in SMemMalloc
heapUsage - Displays heaps in use (Only works in the Console)
hwPCF - Use hardware-based Percentage Closer Filtering for shadows
installType - Type of Installation (Retail/Beta/PTR)
launchThirtyTwoBitClient‎ - Whether to launch 32bit client or 64bit client
lockedWorldMap - Whether the world map is locked when sized down
mapQuestDifficulty - Whether to color quest titles by difficulty in the World Map
mapShadows - Toggle map shadows
maxSpellStartRecoveryoffset - Sets the time in milliseconds before a global cooldown finishes in which a new spell can be queued up
minimapTrackedInfo - Stores the minimap tracking that was active last session
movie - Display intro movie at startup (doesn't work in Burning Crusade game client)
objectFade - Enables the smooth fading of objects after a certain distance
partyStatusText - Toggles the permanent display of health/power texts for party members
patchlist - Address of the WoW patch server
petStatusText - Toggles the permanent display of health/power texts for pets.
playerStatusText - Toggles the permanent display of health/power texts for the player
predictedPower - Whether or not to use predicted power values in the UI
raidFramesDisplayIncomingHeals - Whether to display incoming heals on Raid Frames
readContest - Whether the user has accepted the PTR contest rules
readEULA - Whether the user has accepted the EULA
readScanning - Whether the user has accepted the system scanning terms
readTOS - Whether the user has accepted the Terms of Use
realmListbn - realm list server to use (default: "") - WoW still uses realmList
realmList - Realm list server to use (e.g. "" or "")
reducedLagTolerance - Enables the use of a user-defined value for the spell queuing system introduced in 4.0.3
repositionfrequency - How many frames to skip per nameplate reposition
showGameTips - Toggles displaying of loading screen game tips
showLootSpam - Toggles the detailed display of loot information (loot rolls etc.)
showNewbieTips - Toggles the display of simplified ability tooltips
showRaidRange - Darkens the raid frame of any raid member who is out of range
showToolsUI - Enables the WoW Launcher
showfootprints - Enables footprint display
spreadnameplates - Controls whether nameplates should spread out or overlap
startproject - Results in a disconnect as of 4.0.3
statusTextPercentage - Toggles the permanent display of percentages for status texts on unit frames.
targetStatusText - Toggles the permanent display of health/power texts for the target
textureCacheSize - Caches in memory textures when they are not in use for quick loading. (Min: 8388608, Max: 536870912, Default: 33554432)
unitHighlights - Toggle model highlighting on targeted units
useEnglishAudio - Override the locale and use English audio
useWeatherShaders - Enables weather shaders
worldport - Prints "Teleporting to Stormwind" in the console, but immediately displays an error afterwards