Figured this may interest a few people:
Ni as a third function (ISTP/ISFP):
Find relief with introverted iNtuiting (Ni) - Foreseeing implications, transformations, and likely effects
They can enjoy spending time alone, letting their imaginations plan out a future course of action. They like conceptualizing new ways of seeing things and feel pulled to the symbolic, archetypal, or mysterious. They often get a strong sense that future changes will unfold in a foreseen way and want to make those changes manifest in the real world. They sometimes find comfort in relying on a focal device or symbolic action to predict the best path or help make up their minds. They may be first drawn to trust their intuition when doing creative or technical projects. They will focus on Fulfilling a dream or vision of the future.
When Younger, they tend to distrust most of the impressions they get, such as from dreams or sudden “aha” moments. But as they grow, they begin to listen to that inner voice and follow the vision to take control of their future and actualize their inner potential. They can become quite focused on realizing a vision and creating more long-term strategies.
Engaging in introverted iNtuiting can feel unsettling and disruptive at times. They can lock into a vision, ignoring their usual need for some tangible data. Sometimes they focus on intense imagery or symbols of life's powerful experiences, such as birth and death, explorations that unsettle most others. Or they may engage an inner mystical world that leaves others puzzled.