(Most) Instances by level:

• Ragefire Chasm 13-17 WoWHead
• Wailing Caverns 16-20 WoWHead | WowWiki
• Deadmines 17-20 WoWHead | WoWWiki
• Shadowfang Keep (SFK) 18-21 WoWHead | WowWiki
• Blackfathom Deeps (BFD) 21-24 WoWHead | WowWiki
• The Stockade 23-25 WoWHead | WowWiki
• Gnomeregan 24-28 WoWHead | WowWiki
• Razorfen Kraul (RFK) 24-27 WoWHead | WowWiki
• Scarlet Monastery (SM) 30-32 (GY), 33-35 (Lib), 35-37 (Arm), 36-40 (Cath) WoWHead | WowWiki
• Razorfen Downs (RFD) 34-37 WoWHead | WowWiki
• Uldaman 35-40 WoWHead | WowWiki
• Maraudon 42-48 WoWHead | WowWiki
• Zul'Farrak (ZF) 43-46 WoWHead | WowWiki
• Sunken Temple (ST) 47-50 WoWHead | WowWiki
• Blackrock Depths (BRD) 48-55 WoWHead | WowWiki
• Lower Blackrock Spire (LBRS) 55-60 WoWHead | WowWiki
• Upper Blackrock Spire (UBRS) 55-60 WoWHead | WowWiki
• Dire Maul (East) (DM) 56-60 WoWHead | WowWiki
• Dire Maul (North) (DM) 56-60 WoWHead | WowWiki
• Dire Maul (West) (DM) 56-60 WoWHead | WowWiki
• Scholomance 58-60 WoWHead | WowWiki
• Stratholme 58-60 WoWHead | WowWiki
• Hellfire Citadel: Hellfire Ramparts 60-62 WoWHead
• Hellfire Citadel: The Blood Furnace 61-63 WoWHead
• Coilfang Reservoir: The Slave Pens 62-64 WoWHead
• Coilfang Reservoir: The Underbog 63-65 WoWHead
• Auchindoun: Mana-Tombs 64-66 WoWHead
• Auchindoun: Auchenai Crypts 65-67 WoWHead
• Caverns of Time: Old Hillsbrad Foothills 66-68 WoWHead
• Auchindoun: Sethekk Halls 67-69 WoWHead
• Auchindoun: Shadow Labyrinth 70 WoWHead
• Caverns of Time: The Black Morass 70 WoWHead
• Coilfang Reservoir: The Steamvault 70 WoWHead
• Hellfire Citadel: The Shattered Halls 70 WoWHead
• Tempest Keep: The Arcatraz 70 WoWHead
• Tempest Keep: The Botanica 70 WoWHead
• Tempest Keep: The Mechanar 70 WoWHead

Raids

• Zul'Gurub (ZG) 60+ 20p WoWHead | WowWiki
• The Ruins of Ahn'Qiraj (AQ 20) 60+ 20p WoWHead | WowWiki
• Molten Core (MC) 60+ 40p WoWHead | WowWiki
• Onyxia's Lair 60+ 40p WoWHead | WowWiki
• Blackwing Lair (BWL) 60+ 40p WoWHead | WowWiki
• The Temple of Ahn'Qiraj (AQ 40) 60+ 40p WoWHead | WowWiki
• Naxxramas 60+ 40p WoWHead | WowWiki
• Gruul's Lair 65-70 25p WoWHead
• Black Temple 70 25p WoWHead
• Caverns of Time: Hyjal Summit 70 25p WoWHead
• Coilfang Reservoir: Serpentshrine Cavern 25p WoWHead
• Hellfire Citadel: Magtheridon's Lair 70 25p WoWHead
• Karazhan 70 10p WoWHead
• Tempest Keep: The Eye 70 25p WoWHead