Norse
Njörðr
sea, wind, wealth
Also: Tiānhòu
Chinese tradition. See the whole pantheon.

Believed to be Lin Mo, a girl from Fujian who died in the 10th century. Sailors prayed to her for protection and she is worshipped across Taiwan, Fujian and Southeast Asia.
Deities in other traditions who share a theme with Mazu: sea and waters. This is overlap in one area only.
Norse
sea, wind, wealth
Norse
the sea, brewer of the gods' ale
Norse
drowning, the sea's net
Egyptian
the primeval waters
Egyptian
Nile, fertility, kingship
Mesopotamian
the primeval sea, mother of the gods
Mesopotamian
fresh water below the earth
Mesopotamian
salt water, primordial mother