Key 0000 - Rumours says it once opened every door in Tibia.
Key 0001 - It is unobtainable.
Key 0004 - An old Thais city alpha key. This key is no longer in use.
Key 0005 - An old Thais city alpha key. Key used to open the door to Daemon first demon in tibia. Only a couple are known to exist 3 in Antica 1 on Libera other key unknown due to transfers. Owner on Antica may be Bubble, Nietz, and Tharanic
Key 0006 - Bridgekeepers house. This key is no longer in use.
Key 0007 - An old Thais city alpha key. This key is no longer in use.
Key 0009 - An old Thais city alpha key. This key is no longer in use.
Key 0010 - Used to enter a locked room in the Dawnport outpost.
Key 0020 - Thais Jail key. This key is no longer in use.
Key 0021 - Thais South Gate Guardhouse. This key is no longer in use.
Key 0101 - It opens a door in Bounac's castle.
Key 0303 - It opens several doors in the Cobra Bastion, but it can't be used to close them back.
Key 0555 - It is used to unlock the gate to the Krailos Mines
Key 0808 - Opens the door to the southern tower of the Falcon Bastion.
Key 0909 - It opens two doors on the ground floor of the Falcon Bastion.
Key 3001 - Black Pyramid.
Key 3002 - Black Pyramid.
Key 3003 - Black Pyramid.
Key 3004 - Black Pyramid.
Key 3005 - Black Pyramid.
Key 3006 - Black Pyramid.
Key 3007 - Black Pyramid.
Key 3008 - Black Pyramid.
Key 3012 - Used to enter Hellgate, deep beneath Ab'Dendriel.
Key 3033 - Used to enter/exit the Ab'Dendriel Shadow Caves.
Key 3100 - Old Skjaar key.
Key 3142 - Needed for the Noble Armor Quest.
Key 3200 - Opens door in the Buried Cathedral.
Key 3301 - Found in a dead tree, used to open part of the Bright Sword Quest area.
Key 3302 - Found in a dead tree, used to open part of the Bright Sword Quest area.
Key 3303 - Found in a dead tree, used to open part of the Bright Sword Quest area.
Key 3304 - Used to open the door to the Bright Sword Quest reward room.
Key 3350 - Key for the Isle of the Kings.
Key 3520 - For access to the Carlin Graveyard.
Key 3600 - Opens the door to the Ghoul Room Quest.
Key 3610 - Opens the door to the secret laboratory in Mintwallin.
Key 3620 - Provides access to the prison in Mintwallin.
Key 3650 - Opens the door to the Mintwallin Storage Room.
Key 3666 - Opens the door for the Mad Mage Quest.
Key 3667 - Opens the door in the Cyclops room over Minotaur Outcasts' camp where Key 3610 is.
Key 3700 - Pits of Inferno quest room key.
Key 3701 - Opens door in the Necromant House.
Key 3702 - Once opened the door to the Knightwatch Tower.
Key 3703 - Seen on the way to Pits of Inferno.
Key 3800 - Opens a door in the throne room in Kazordoon.
Key 3801 - Opens a door near the armory in Kazordoon.
Key 3802 - Opens the door to Dwacatra.
Key 3899 - Opens a door for the Paradox Tower Quest.
Key 3900 - Old guild hall key. This key is no longer in use.
Key 3901 - Old guild hall key. This key is no longer in use.
Key 3902 - Opened Opa Wetterwachs Tower.
Key 3909 - Old guild hall key. This key is no longer in use.
Key 3910 - Old guild hall key. This key is no longer in use.
Key 3911 - Old guild hall key. This key is no longer in use.
Key 3912 - Old guild hall key. This key is no longer in use.
Key 3913 - Old guild hall key. This key is no longer in use.
Key 3914 - Old guild hall key. This key is no longer in use.
Key 3915 - Old guild hall key. This key is no longer in use.
Key 3916 - Old guild hall key. This key is no longer in use.
Key 3917 - Old guild hall key. This key is no longer in use.
Key 3923 - Old guild hall key.
Key 3925 - Old guild hall key.
Key 3930 - Mercenary Tower key. Comes in wooden and copper variants. This key is no longer in use.
Key 3931 - Mercenary Tower key. This key is no longer in use.
Key 3932 - Mercenary Tower key. This key is no longer in use.
Key 3933 - Mercenary Tower key. This key is no longer in use.
Key 3934 - Mercenary Tower key. This key is no longer in use.
Key 3935 - Mercenary Tower key. This key is no longer in use.
Key 3936 - Mercenary Tower key. This key is no longer in use.
Key 3937 - Mercenary Tower key. This key is no longer in use.
Key 3938 - Mercenary Tower key. This key is no longer in use.
Key 3940 - Used to enter/exit the Fibula Dungeon. Comes in wooden and copper variants.
Key 3950 - Old Cyclops area in Fibula. This key is no longer in use.
Key 3960 - Opened the Flute Room in Fibula. Comes in wooden and bone variants. This key is no longer in use.
Key 3970 - Old Fibula key. This key is no longer in use.
Key 3980 - Opens the Deeper Fibula Quest area.
Key 3988 - Old guild hall key. This key is no longer in use.
Key 4001 - Fire Devil Pit key here
Key 4009 - Opens the Desert Dungeon Library.
Key 4022 - Allows access to the room holding Key 4009.
Key 4023 - Desert Dungeon Teleport Room key.
Key 4033 - May be used in the Desert Dungeon.
Key 4037 - Hall of Lost Doors.
Key 4055 - Access to the Panpipe Quest.
Key 4210 - Old guild hall key. This key is no longer in use.
Key 4501 - Used to enter/exit Alawar's Vault storage room.
Key 4502 - Used to enter/exit Alawar's Vault.
Key 4503 - Used to enter/exit the Restricted Area in the Folda dungeon.
Key 4600 - Training Room in the Rookgaard Academy. This key is no longer in use.
Key 4601 - Key to the Bear Room.
Key 4602 - May not exist. May be the key of the Minotaur Mage room.
Key 4603 - Katana Quest Room in Rookgaard.
Key 5000 - Wyda's house.
Key 5002 - Used to open a door in the Black Knight's Villa. This key is no longer in use.
Key 5010 - Opens door to the Black Knight's Villa.
Key 5050 - Angelina's cell in Dark Cathedral.
Key 6010 - Access to the Demon Hell.
Source: Keys | TibiaWiki | Fandom