The Vaikhanasamantraprasna contains this gayatri mantra
rājarājāya vidmahe
dhanādhyakṣyāya dhīmahi
tan nas somaḥ pracodayāt
Monier-Williams identifies dhanādhyakṣya as Kubera.
Is this a gayatri mantra to Kubera or to Soma as the moon, or to the elixir Soma?