Skills
Alchemy/TL5^ & Herb Lore/TL4^, in the absence of powers like Psychography and Astral Binding, above (or other abilities, triggered by using these skills, or by items created with them), provide a semi-reliable understanding of psychobotanics and similar psi-drugs (see 'Old Time Psi,' GURPS Psionic Campaigns, p5 boxed text). This is done at a penalty of -5 to find or invent a preparation that both works and is useful for your purpose (as opposed to poison or useless filler), in addition to other factors, like Complexity (if inventing) or working conditions. The penalty does not apply to recipes that have already been established to work, if you know of them. Poisons is a Complementary Skill.
Area Knowledge (Astral) covers both the Inner Astral Plane, and interesting or dangerous locations in the Outer Astral Plane (areas of persistent Psi Static, places with strong or weak barriers (see Astral Travel under New, Modified, or Unavailable Abilities, above), haunted houses, homes of important or interesting Astral psis, et cetra). For individuals with Astral Sight or Astral Travel, and some with Spirit Communication, regional Area Knowledge includes knowledge of the Outer Astral Plane in that region.
Autohypnosis & Meditation are nearly always Complementary Skills for psi abilities, even if not used as trigger skills. Being unable to use one or both as Complementary Skills for your psi abilities counts as a quirk if you have either or both skills, or a feature if you have neither.
Current Affairs (Psionics) can be considered a combination of psi-specialized versions of CA (Headline News), CA (People), and CA (Science & Technology). You know about recent discoveries, Who's Who among the more powerful or effective psis and psychical researchers, and what major incidents are ongoing or recently occurred.
Dreaming is used as a triggering skill for a number of abilities, primarily Dream Control (of course), Astral Projection, and Telepathy, and sometimes Psychic Healing or Probability Alteration; one fairly common ability triggered by Dreaming is Spirit Communication. Psychics who use Dreaming for active abilities often use Fortune-Telling (Oneiromancy) as a triggering skill for sensory and divinatory powers.
Esoteric Medicine comes in a wide range of required specialties, any of which may be used as a triggering skill. In the absence of powers, these skills vary from 'not as good as Physician/TL6^, but noticeably better than First Aid' to 'about as good as First Aid in the short term, but detrimental to the medium- or long-term health of both the patient and the healer,' generally depending as much on what's being treated as on which tradition is being used. Unless the GM determines otherwise, Esoteric treatments should average to 'about as good as First Aid.'
Fortune-Telling specialties make good trigger skills, not only for sensory and divinatory abilities, but for Probability Alteration and other powers, as well: though rather less common, it is certainly
possible to use tools like tarot cards or sacred dice for active abilities. Generally, using Fortune-Telling to trigger an active ability involves working backwards, by choosing the cards, dice, or whichever for the intended result. Ritual Magic and Symbol Drawing are Complementary Skills for some specialties.
Hidden Lore specialties include Psis, Spirits, Astral, Faeries, Demons, Angels, Ultraterrestrials, and specific conspiracies or practices, like Freemason Lore or Qabala Lore. While Faeries, Demons, Angels, and Ultraterrestrials are all spirits, and spirits are all astral entities, the various specializations do cover different areas: each group has its own society or societies, while Spirit Lore covers spirits in general, and especially those that do not fit in the other categories, and Astral Lore is more environmental, covering the secrets of the Astral Plane, not specifically its denizens. Note the distinction that Hidden Lore refers to matters that are obscure, as opposed to skills like History, Current Affairs, or Area Knowledge, which cover things that anyone may have access to.
Pharmacy (Psi)/TL6^ is a skill in development, and is currently quite limited, only covering the small number of psi-drugs that have not only been found to work, but have been properly studied, refined, and synthesized in a laboratory. This is a new science, and is poorly understood. GMs may wish to set a maximum skill level, or number of points that can be spent on it (e.g. limiting it to skill 9, or to one point, or even to being part of a Dabbler perk). The GM should look through Psi-Tech (and perhaps Ultra-Tech & Bio-Tech), and make a list of which psi-drugs or other unusual chemicals are currently available.
Ritual Magic and Symbol Drawing may be used as triggering skills, or to analyze the triggers or attuned items of those who use the same style or lexicon, but have no power on their own. They sometimes are used by stage magicians or con artists to assist them in
faking powers, though. There is little point in purchasing specific symbols in this setting, but Paths and Books may be available if the GM wishes. If so, they should be treated as specialized social skills, with the rituals being fairly standard contracts that, depending on the spirit's Reaction Roll, may need a little negotiation (they should
not be treated as spells, in other words).
Weird Science/TL6^ covers a wide range of fringe theories in this setting, none of which are so developed as to require specialization. It works well as a triggering skill, and is the basis for most 'psychotronic' devices. In the absence of power, it may be completely useless beyond analyzing the works of other psychics who use Weird Science, or it might be of limited use on its own, if the GM feels that some fringe theories have a basis in (this) reality.
Thoughts?