Ghosts: Psionic residues of dead persons. A living person with high Psi-Strength (PSI 5+ if trained in Telepathy, PSI 8+ if untrained) could detect these residues ("see ghosts") for 3d6 after a person's death (partially based on Babylon 5 and much more on System Shock 2). People who die in an emotionaly intense situation tend to "stay behind" longer - DM +6 to that time roll.
Propecies and Prophetic Dreams: Only Droyne Drones with Coynes can make vaguely accurate predictions. However, people with high PSI and a "Special" talent (I'd make it Special 7) can have dreams that show to them one possible outcome of a timeline. One of many... Think of the dream that Centauri woman had in Babylon 5, seeing the station explode (which was averted two seasons later on). A good way to introduce metaplot foreshadowing...
Ghost Ships: Ships run by a sentient or semi-sentient computer after their crew was killed. Not nescerily malevolent (sp?) but most likely alien in its behavior. TL15+ typically.
Shamans: PSIs from lower-TL worlds, or PSIs from higher-TL areas who like an aura of mystery around them, or just con-men (good Forgery, Streetwise and Carousing skills).
Alien Ghosts: Actually "psionic recordings" using high-TL (?) technology of a dead culture (see the Martian Gothic computer game or the Ghosts of mars film for ideas).
"Bad Places": Places, especially worlds, with a reputation of "bad luck" and strangeness. Mars in the Sol system is a good candidate. Explanation could be anything from poure superstition, through hidden (and atleast partially active) alien relic technologies to a world-wide "planetary conscousness" (think the "Solaris" book) with PSI.