The Citadel was a Crucible map located in the Dreaming City in the Reef. It was vaulted with the release of Beyond Light. Destiny 2 Game Director Joe Blackburn has confirmed that the map will return to the game during the final Season of Lightfall, Season of the Wish. According to Jeff Horal, Senior
The Juncture, Destiny Wiki
Midtown - Destinypedia, the Destiny wiki
Legion's Gulch - Destinypedia, the Destiny wiki
Black Garden - Destinypedia, the Destiny wiki
Disjunction - Destinypedia, the Destiny wiki
Bannerfall - Destinypedia, the Destiny wiki
Fallen, Destiny Wiki
Exodus Blue - Destinypedia, the Destiny wiki
The Reef - Destinypedia, the Destiny wiki
Hive, Destiny Wiki
Vault of Glass (raid) - Destinypedia, the Destiny wiki