WoW Instances by level in TBC Classic, a breakdown of each dungeon, and they're organized according to the level range. 
Some dungeons in TBC Classic require that previous quest chains be completed in order to be able to enter them. Other dungeons are required to complete your Karazhan attunement.

The location of the dungeon is indicated by a bolded portion, which is followed by the name of the dungeon itself, WOW TBC classic gold is available, from aoeah.com.

In TBC Classic, the WoW instances are sorted by level.
Dungeons of Hellfire Citadel
Hellfire Citadel (also known as Hellfire Citadel) is a fortress in Hellfire. Ramparts: 60-62
Hellfire Citadel: The Blood Furnace (levels 61-63).
Hellfire Citadel: The Shattered Halls (Levels 69-70)

ZANGARMARSH DUNGEONS (Zangarmarsh Dungeons)
The Slave Pens at Coilfang Reservoir are numbered 62-64.
The Underbog at Coilfang Reservoir is 63-65 degrees Fahrenheit.
The Steamvault at Coilfang Reservoir is 68-70 degrees Celsius.

Terokkar Forest Dungeons are a series of dungeons located in the Terokkar Forest.
Auchindoun: Mana-Tombs: 64-66
Auchindoun: Auchenai Crypts: 65-67
Auchindoun: Sethekk Halls (numbers 67-69).
Auchindoun: Shadow Labyrinth (levels 69-70)

Tempest Keep Dungeons are a series of dungeons in the Tempest Keep.
Tempest Keep: The Botanica (70)
Tempest Keep: The Mechanar (70)
Tempest Keep: The Arcata: 70

Azeroth Dungeons are a series of dungeons that can be found throughout Azeroth.
Caverns of Time: Old Hillsbrad Foothills: 66-68
Caverns of Time: The Black Morass (Level 70)

Additionally, Magisters' Terrace is a level 70 dungeon that will not be accessible until the final phase of TBC Classic, Phase 5, when the Isle of Quel'danas is released.