Energy Healing
A common energy healing orb could only mend a single astral entity by transferring the mental energy of the user to the recipient. The rare variant, on the other hand, had the capability to heal more than one, yet it still adhered to the same fundamental concept—energy transfer.
This explained why energy healing wasn't a sought-after among citizens and mentalists. The former were inherently individualistic, driven solely by personal gain. The ability to transfer one's mental energy seemed to be a useless ability to them.
This was especially true for the latter as well. While the orb was useful for treating recurring mental problems, that was its sole application. Many still preferred not to incorporate it into their three chosen psychic abilities.
However, this concept changed when it became a 'very rare' variant. Not only could it heal others, but it also granted the user the ability to heal themselves.