Here, you can find a list of useful IDs for displays, factions, flags, etc. in World of Warcraft. Obviously, this data is useful for GMs or Admins of private WoW servers. Most spreadsheets are taken/compiled/arranged from DB2/DBC data.
ChrClasses (Info from ChrClasses.db2)
ChrRaces (Info from ChrRaces.db2)
Emotes (Info from Emotes.db2)
Factions (Info from FactionTemplate.db2, Faction.db2)
ItemVisuals (Info from ItemVisuals.db2. A nicer-formatted list of weapon enchants is here)
Maps and Areas (Info from Map.db2 and AreaTable.db2)
Movies (Info from Movie.db2, MovieVariation.db2, and CinematicCamera.db2)
Phases (Info from Phase.db2)
Spells (Info from Spell.db2, SpellMisc.db2, SpellCastTimes.db2, SpellDuration.db2, and SpellRange.db2)
WorldMapArea (Info from WorldMapArea.db2)
ChrRaces (Info from ChrRaces.dbc)
CreatureInfo (Info from CreatureDisplayInfo.db2, CreatureModelData.dbc, and CreatureDisplayInfoExtra.dbc. AKA Morph IDs)
Emotes (Info from Emotes.dbc)
Faction IDs (Info from FactionTemplate.dbc and Faction.dbc)
Flags and Types (Various flags (e.g., unit_flags, standstates, etc))
GameObjectDisplayInfo (The format was changed since Cata, but this still contains Model IDs and names)
Maps and Areas (Info from Map.dbc and AreaTable.dbc)
Mounts (Info from Mount.db2, MountCapability.db2, MountTypeXCapability.db2, and MountType.db2. Unsure of purpose of MountTypeXCapability, but Mount.db2 may be useful to see a list of all normal mounts. MountType seems to just be a list of mount types now.)
SoundIDs (Info from SoundEntries.db2. This time around, I can't seem to find filenames for the individual 'parts' of any particular sound entry - that is, if an entry has multiple sounds associated with it. However, the main sound name should be good enough to find what you need!)
WorldMapArea (Info from WorldMapArea.dbc - This contains info involving what areas are contained in the world map (e.g., subzones))
CharTitles (Info from CharTitles.dbc)
Currency and ItemExtendedCost (Info from CurrencyTypes.dbc, ItemExtendedCost.dbc)
Faction IDs (Info from FactionTemplate.dbc, Faction.dbc)
Maps and Areas (Info from Map.dbc, AreaTable.dbc)
Sound IDs (Info from SoundEntries.dbc)
Spell IDs (Info from Spell.dbc, SpellCastTimes.dbc, SpellDuration.dbc, SpellRange.dbc, SpellVisual.dbc, SpellIcon.dbc, SpellDifficulty.dbc, SpellScaling.dbc, SpellAuraOptions.dbc, SpellCastingRequirements.dbc)
CreatureDisplayInfo[Extra] + CreatureModelData (Info from CreatureDisplayInfo.dbc, CreatureModelData.dbc, CreatureDisplayInfoExtra.dbc. AKA Morph IDs)
ChrRaces (Info from ChrRaces.dbc)
ItemDisplayInfo (Info from ItemDisplayInfo.dbc (can assist with finding items from a similar color scheme), Item.db2)
GameObjectDisplayInfo (Info from GameObjectDisplayInfo.dbc (Model IDs and Names), also includes some pertinent info from gameobject_template)
Reputation IDs [3.3.5]
Chair IDs (With pictures! [3.3.5])
Table IDs (With pictures! [3.3.5])
Faction IDs Info [6.2.4/4.3.4/3.3.5]
Notable XYZ Locations (Editable by GMs)
Holiday Objects List (Gameobjects, Items, NPCs - Editable by GMs)
Unnamed Gameobjects (GOs with an empty name)