From LOTR-TCG Wiki

Errata is an edit to a card's game text after its printing, mainly to nerf or fix a card with too much power or a looping mechanism. (Errata is technically plural, but nobody ever says "erratum".) Decipher has issued errata for several cards, such as The Mirror of Galadriel (1R55)LOTR-EN01S055.0 card.jpg, Sting of Shelob (18R35)LOTR-EN18S035.0 card.jpg, and Howl of Harad (4U236)LOTR-EN04S236.0 card.jpg. Decipher issued more errata in Rise of Saruman and Treachery & Deceit than any other sets, due to their hasty production process. The final errata issued occasionally did not either repair the card or instead made the card unplayable, for example Frenzy of Arrows (18U79)LOTR-EN18S079.0 card.jpg.

The Players' Council fan group is working on their own project to errata useless, broken, or X-Listed cards.

Game Setup Starting FellowshipBiddingMulligan
Deck Building Considerations UniquenessX-ListR-ListErrataFormat
General Strategies BeatdownBombCorruptionDirect Wounding/Undirected WoundingHand ExtensionRun/StopSkirmish CancellationSwarmWin ConditionWound Prevention
Deck Archetypes Auto-Corruption BombBeasterlingsElventsForestgulsHobbit HospitalFruit LoopsGondor KnightsGondor RangersGondor WraithsMoria ArcheryMoria BeatdownMoria NavyMoria SwarmMoria TentaclesNazgul BeatdownNinja GollumOrc CorruptionRainbow WoundingSauron GrindSauron InitiativeSauron RoamingSauron ThreatsSolo SmeagolSouthron ArcherySouthron InitiativeStupid SwarmSuper FriendsTelepathyThreatgulsToken TanksTroll SwarmUruk ArcheryUruk MachinesUruk TrackersWarg Super Swarm
Rules Rule of 4Rule of 9
Mechanics BearDiscardDraw DeckExertExhaustedFellowshipInitiativeIn Play/Leave PlayMove LimitReconcileRoamingSite ControlSpotStackSupport AreaThreats
Gameplay Terms BoatBodyBroken/NPE/OPBuff/NerfChokeChump BlockingComboCultural EnforcementCyclingDead DrawFatFilterFloodGasGlueGrindHand ClogHateInteractionLoopMatchupMetaMillNewbie TrapNukePilePower CreepPumpRainbowRecursionRemovalResourceRogueRule of 6SideSite ManipulationSplashSubcultureTankTutor/DownloadValue EngineWhiff