Delver of the Depths

Breaking Down Delves by Zone:

Isle of Dorn:
Earthcrawl Mines (/way #2248 38.7 73.6)
Kriegval’s Rest (/way #2248 62 42)
Fungal Folly (/way #2248 52.3 66.0)

Hallowfall:
Skittering Breach (/way #2215 66.6 61.7)
Nightfall Sanctum (/way #2215 35.1 46.2)
Myomancer Cavern (/way #2215 71.2 31.1)
The Sinkhole (/way #2215 50.6 50.7)

The Ringing Deeps:
The Waterworks (/way #2214 46.2 48.0)
The Dread Pit (/way #2214 73.6 38.4)

Azj-Kahet:
The Spiral Weave (/way #2255 45.5 21.6)
Tak-Rethan Abyss (/way #2255 54.8 72.6)
The Underkeep (/way #2216 57.3 64.9)
Zekvir's Lair (/way #2216 9.8 33.8)

Thanks to kplicious, here is the list for those with PasteNG & TomTom
/way #2248 38.7 73.6 Earthcrawl Mines
/way #2248 62 42 Kriegval’s Rest
/way #2248 52.3 66 Fungal Folly
/way #2215 66.6 61.7 Skittering Breach
/way #2215 35.1 46.2 Nightfall Sanctum
/way #2215 71.2 31.1 Myomancer Cavern
/way #2215 50.6 50.7 The Sinkhole
/way #2214 46.2 48 The Waterworks
/way #2214 73.6 38.4 The Dread Pit
/way #2255 45.5 21.6 The Spiral Weave
/way #2255 54.8 72.6 Tak-Rethan Abyss
/way #2216 57.3 64.9 The Underkeep
/way #2216 9.8 33.8 Zekvir's Lair

The Underkeep (Azj-Kahet) is inside the City of Threads open world subzone. On the main Azj-Kahet map it's at 51.9,88.2 - kplicious' coords are correct once you get into the City of Threads map. And despite its name, it's not on the lowest level.