Great Old One patron

A Great Old One patron was one possible sponsor for a warlock. If a bargain was made between a warlock and a being from the Far Realm, an elder evil, or some other ancient and mysterious being, the warlock's patron gave them access to certain powers, including a suite of spells that expanded the choices to fill their spell slots.

Great Old One patrons
List of Great Old One patrons

Great Old One patron expanded spells

 * 1st level : dissonant whispers, Tasha's hideous laughter
 * 2nd level : detect thoughts, phantasmal force
 * 3rd level : clairvoyance, sending
 * 4th level : dominate beast, Evard's black tentacles
 * 5th level : dominate person, telekinesis