Is there a word for creating something or bringing something into existence just by thinking it? Something besides materializing.
Manifesting would work. You can use a form of it as a noun:
The dragon was a manifestation of her imagination.
Or as a verb:
Manifest: verb 1. display or show (a quality or feeling) by one's acts or appearance; demonstrate. "Ray manifested signs of severe depression" synonyms: display, show, exhibit, demonstrate, betray, present, reveal; formalevince "she manifested signs of depression"
For your purposes, you might say that the people of planet zoltrax were able to manifest anything they needed simply by the power of their thoughts.
edited to expand