I haven't forgotten about the Role Archetypes series, but I'll be postponing it another while because I'm working on Jupiter Sovereign.
In Jupiter Sovereign, each character has one or two domains of psionic proficiency. Technically, psionics can boost any "tag" that they use, but each domain gives an additional tag and also allows the character to get a special boost beyond that.
For context, in some variants of Hermetic alchemy, the zodiac signs are used as stand-ins for the twelve processes required to create a Philosopher's Stone; this is both a way to keep them secret so that outsiders don't know what the alchemist is referring to and a short-hand to let the alchemist record it quickly.
Here on Steem, you'll probably see the alchemical symbols below in the Unicode format that has a purple box behind them, but in the text we use a font that prints them as standard characters, so you won't be reading a book that looks like it was written on a cell-phone. I've included an example below:
See, this looks a lot better! Well, maybe. I don't like the Capricorn symbol as a matter of personal taste.
Signs
A character may select up to two Signs at the cost of two character points each. A character with no signs may still be a psion and an alchemist, but they are not "trained" as one in the tradition of Adomas and cannot perform any of the steps of creating a Philosopher's Stone or benefit from the effects of a Stone.
A character may not ever have the same Sign twice, and they may not have more than two Signs, even after character creation. A character may gain a Sign later during character advancement if they do not hit the limit during character creation.
♈ Aries
Aries is associated with calcination, the act of heating a substance to an extreme degree. Psions who are versed in this domain gain the "fighter" tag, which can be applied to almost any conflict, and also gain an extra Psionic Boost point to a roll so long as they spend at least two points to boost that same roll.
Author's note: Mechanically, a +3 boost allows things that are theoretically impossible; characters can only boost equal to the tags that they have (doubling the bonus dice they get), and this mechanic allows them to bypass this limitation.
♉ Taurus
Taurus is associated with congelation, the act of a substance forming a solid or thickening. Psions who are versed in this domain gain the "harmonious" tag, which can be applied to most social situations. They may apply Psionic Boosts to other characters' actions using their own pool; when they do so they also benefit from any bonuses that the other character applies to their own Psionic Boosts.
♊ Gemini
Gemini is associated with fixation, the act of taking a volatile substance and turning it into something not susceptible to fire. Psions who are versed in this domain gain the "stasis" tag, which can be used to prevent changes and exertions of energy in most situations. If they use a Psionic Boost for a reaction, they may choose the result of one die after they roll.
♋ Cancer
Cancer is associated with dissolution, the action of breaking down a compound into parts. Psions who are versed in this domain gain the "dynamism" tag, which can be used to assist changes and exertions of energy in most situations. If they use a Psionic Boost to add bonus dice, they add one extra die after all points are spent.
♌ Leo
Leo is associated with digestion, the act of consistently applying a gentle heat to a substance. Psions who are versed in this domain gain the "survivor" tag, which can be used whenever they are trying to endure or resist a threat. If they use a Psionic Boost on a roll, they roll an additional die on the next test they roll for.
♍ Virgo
Virgo is associated with distillation, the act of boiling and condensing to separate distinct elements of a solution. Psions who are versed in this domain gain the "discernment" tag, which can be used to separate two things (and also to determine truth and falsehood). They may always choose to use Psionic Boosts after they have rolled (for all purposes, not just rerolling).
♎ Libra
Libra is associated with sublimation, the act of taking a substance from a solid to a gaseous state. Psions who are versed in this domain gain the "alteration" tag, which can be used to modify properties or appearances of objects and creatures. They may use a Psionic Boost to change one of their beneficial tags into another beneficial for an arbitrary period. They may only do this for one tag at a time, and they must be familiar with the tag that they are choosing. At the GM's discretion, this may require a pure psionics test of a difficulty relative to the rarity of the chosen tag.
♏ Scorpio
Scorpio is associated with separation, the act of using a substance to create multiple distinct products. Psions who are versed in this domain gain the "duplication" tag, which can be used with pure psionics to create duplicates of an inanimate object; the Potency is based on the complexity and size of the duplicate, and the Threshold is determined by the number of duplicates created. The duplicates last for around three hours and are identical copies; Psionic Boosts can extend this exponentially.
Author's note: I'm not entirely sure how to handle pure psionics, and this rule will obviously require more elucidation in the final work.
♐ Sagittarius
Sagittarius is associated with ceration, the act of using a liquid to soften a solid substance. Psions who are versed in this domain gain the "alteration" tag, which can be used with pure psionics to alter a substance's properties temporarily. The Potency is based on the required changes (e.g. state of matter, reactivity, radioactivity, and so forth) and the Threshold is based on the volume of altered material. The effect lasts for around three minutes, and only work on relatively homogenous compounds (like a vat of liquids or the hull of a spacecraft); Psionic Boosts can extend this exponentially.
This is not alchemical transmutation; the material behaves differently only in the ways that the psion specifies and the change is temporary.
♑ Capricorn
Capricorn is associated with fermentation, the act of using biological processes to transform a substance. Psions who are based in this domain gain the "biochemical mastery" tag, which is used whenever they attempt to alter a creature's biochemistry (e.g. when performing medicine or augmentations, poisoning, or the like). If the character uses a Psionic Boost on a roll where the biomancer tag applies, the first point expended applies all three Psionic Boost effects simultaneously.
♒ Aquarius
Aquarius is associated with multiplication, the act of infusing power in the Philosopher's Stone or other psionic effects. Psions who are based in this domain gain the "amplifier" tag, which they apply to any assisted action they are involved in. If the character activates three points worth of Psionic Boost on a single action (including bonus points gained from other domains), they restore may restore one point of Psionic Boost to each of two other psions immediately.
♓ Pisces
Pisces is associated with projection, the final act in the alchemical process of creating a Philosopher's Stone. Psions who are versed in this domain gain the "completion" tag, which is used when the character's test has a chance of finishing a complex action. This domain has no other effects outside the presence of a Philosopher's Stone or the finished components required to create one (a 5x5 simple test; failure destroys the components and the psion's ability to use Psionic Boosts in the future). In the presence of a Philosopher's Stone, a character with this Potential gets a 1 point Psionic Boost constantly on every test they attempt, in addition to the Stone's other effects.
Obvious caveat: I just made all these game rules and they're still really hot off the presses. Terms, explanations, and probably even game mechanics are not final.