There’s 10 Mythic dungeons in total at the release of Battle for Azeroth. 2 of them are Mythic only dungeons, locked behind story progression. To get you going quickly we have prepared 2-3 minute quickstart guides for the changes of each of the dungeons!
Mythic Only Dungeons
Siege of Boralus
Mythic Dungeons Of Leveling Dungeons
Shrine of the Storm
Temple of Sethraliss