Was there any distinctive clothing which depicted Sumerian gods (Anunnaki) and their ranks? Like wearing helmets with horns?
Few examples:
Akkadian Cylinder Seal of Adda (c. 2250 B.C.) with, left to right, Ninurta, Ishtar, Shamash, and Ea. From Dury, Art of the Ancient Near and Middle East, Abrams, NY
Akkadian Cylinder Seal (c. 2200 B.C. showing Gilgamesh slaying the bull of heaven, with Enkidu? Also from Dury; both in British Museum)
Image sources: tulane.edu
The four-tiered headress is frequently repeated in representations mesopotamian deities.
Some other examples include:
A bust of an unknown god
the Burney Relief,
which depicts either Inanna or Ereshkigal.
A relief of Enki
Depiction of Shamash on a Hammurabi stele
These do seem to be worn by the most important deities, which seems to line up roughly with the gods Samuel Noah Kramer identifies as the "Gods who Decree", which includes: Anu, Enlil, Enki, Ninhursag, Inanna, Nanna and Shamash. If we conclude the Burney Relief is Ereshkigal, then perhaps her too, I suppose.
Lesser gods seem to often wear hats like this one (shown on Nergal):
As far as the horned helmet on the lower seal, the fellow on the right (probably Enkidu) has noticeably bovine legs and tail. The horns are probably not intended to be a helmet, but rather part of the depiction of him being half-animal. Similar depiction seen here:
