The illithid pantheon is only made up of two deities. The leader of the pantheon is Ilsensine. Maanzecorian, the only other power in this pantheon, is reputably dead at the hands of Orcus.
This pantheon counts among its enemies most of the powers of the Material Plane. It’s most prominent enemies are the Duergar Pantheon and the Derro Pantheon.