WoW Instances by level in TBC Classic, a breakdown of each dungeon and their according level range.
Some dungeons in TBC Classic require previous quest chains to be completed in order to enter them. Other dungeons are essential in completing your Karazhan attunement.
The bolded portion is the location of the dungeon, followed by the name of the dungeon itself.
WoW Instances by Level in TBC Classic
Hellfire Citadel Dungeons
Hellfire Citadel: Hellfire Ramparts: 60-62
Hellfire Citadel: The Blood Furnace: 61-63
Hellfire Citadel: The Shattered Halls: 69-70
Coilfang Reservoir: The Slave Pens: 62-64
Coilfang Reservoir: The Underbog: 63-65
Coilfang Reservoir: The Steamvault: 68-70
Terokkar Forest Dungeons
Auchindoun: Mana-Tombs: 64-66
Auchindoun: Auchenai Crypts: 65-67
Auchindoun: Sethekk Halls: 67-69
Auchindoun: Shadow Labyrinth: 69-70
Tempest Keep Dungeons
Tempest Keep: The Botanica: 70
Tempest Keep: The Mechanar: 70
Tempest Keep: The Arcatraz: 70
Caverns of Time: Old Hillsbrad Foothills: 66-68
Caverns of Time: The Black Morass: 70
Additionally, Magisters' Terrace is another level 70 dungeon, but not available until the final Phase of TBC Classic, Phase 5 when Isle of Quel'danas is released.