Options for Swords & Wizardry Complete: Psionics (2013)

from the introduction:
This product is written specifically for use with Swords & Wizardry: Complete by Mythmere Games and currently available from Frog God Games. Page references given are for the latest publicly available edition of those rules. With a bit of tweaking this system may also be used any mid-1970's era FRPG or compatible rules.

Psionic ability, or simply "psionics," denotes the powers of mind. These powers are similar to magic in that they do not obey the natural laws of physics or cause and effect; instead they more closely resemble magic. These rules were envisioned for use with the various man-type races in a typical campaign milieu. It should be noted that, due to its rarity of occurrence, this system for psionics may be extended to any race or character without unbalancing play.

user note:
This supplement is available as either a one-up PDF for screen reading or single-sided printing on invoice size paper, or as a two-up PDF formatted for printing a booklet using letter-size paper. The content of both versions is the same.

This sourcebook is available as a free download from the publisher.