Halatali LV20 = NPC just outside Waking sands

Sunken Temple of Qarn LV35 = same NPC as Halatali but must complete Halatali to unlock it

Cutter Cry LV38 = NPC near Bazaar in Uldah Steps of Thal Must Defeat Titan to Unlock it

the rest of dungeons from lv15 to lv32 are required to be done in main storyline

thats all i got i will update as i progress more