A hive mind was an instance in which multiple beings were controlled by one shared mind. Some species, like Killiks and Taurill, naturally featured hive minds. The Ithorian experimental creature Spore, on the other hand, was capable of absorbing other beings into its consciousness, creating a hive mind which it ruled.
The Bilars were a sentient species of mammals whose members bonded into groups known as claqas who shared a group mind. Such pooling of intelligence meant that the more Bilars had been bonded into a single claqa, the more intelligent the group would be. The biological mechanisms involved in this process were ill understood by scientists, but they seemed to include a mixture of pheromones, physical touch, and telepathy.
*Episode I Adventures Game Book 4: Jedi Emergency (Mentioned only)
*Labyrinth of Evil
*Coruscant Nights II: Street of Shadows
*Galaxy of Fear: Spore
*X-wing: The Krytos Trap (Mentioned only)
*Dark Nest I: The Joiner King
*Dark Nest II: The Unseen Queen
*Dark Nest III: The Swarm War