These are more like suggestions for Arcana Unearthed purists who really want to build something specific. They're supposed to represent the "archetypal heroes" of the Land of the Diamond Throne.

Akashic
The akashic is a guy who can tap into the collective unconscious and access the combined knowledge of everyone who's ever lived. They're skilled craftsmen, but also are experts in ancient lore and occasionally operate as spies.
Primary - Craft (or maybe Artistic).
Secondary - Artistic (or maybe Craft), Illicit, Social.
I'm still trying to figure out how the magical Akashic Memory works, so this is all provisional. I'd suggest going with the Secret of the Polymath (an Elf species secret from the TSOY main book), but use Storytell instead of Past Lives as the related skill. Other possible secrets: Knowledge (a Human species secret from TSOY), Evaluate, Hidden Knife, Eleazar's Generalship (listed on the wiki as a Maldor cultural secret).

Champion of X
A champion is a knight dedicated to a metaphysical cause: Life, Death, Freedom, Tyranny... or even something concrete, like the Royal Family. Champions are big, tough people who wallop people in the service of the cause.
Primary - Fighting.
Secondary - Priestly, Social.
There are a lot of fightin' classes in Arcana Unearthed, and the champion is just one of them. The really distinctive thing about the champion is her metaphysical connection, which confers various kewl p0werz--Secrets in terms of this game. I'd recommend the Secret of Imbuement, to create a weapon that gives a +2 combat bonus in service to a specific cause, and the Secret of Enhancement (Bash and Hold). The Secret of Blessing might work too, or anything appropriate to the champion's cause. The Key of Faith is probably advisable.

Greenbond
Arcana Unearthed's druid, although she's not called that.
Primary - I'm thinkin'--probably Priestly
Secondary - Outdoor.
Greenbonds wield the power of the Green--the magic of living, natural things. They're powerful healers and can talk to nature-spirits. I'm still working out how Green magic should work in the Solar System, but some of their "class secrets" would include the Secret of Herbal Health and the Secret of Animal Speech.

Mage-Blade
To people familiar with the Dungeons & Dragons system, this is a fighter/mage multi-class, except it's a single class. (Yeah, like that sentence made any sense!) Anyway--the concept is, here's some swordsman who also happens to know some simple magical spells, mostly related to buffing himself for combat. Primary - Fightin'
Secondary - Hmmm - still don't know how Eldritch Magic is supposed to work.
Mage-blades have minor spell-casting abilities, and can use their favored weapon to slice through enchantments. A mage-blade definitely has the Secret of the Signature Weapon, and probably the Secret of Imbuement (+2 when the enemy's got magic flyin' arouund).

Magister
The wizard-priests of Arcana Unearthed, and masters of Eldritch magic.
Primary - hmm - Priestly I suppose.
Secondary - Social? Craft? Artistic?
As of late February I have no clue how to handle Arcana Unearthed's style of magic in the Solar System; for right now, I guess the Three Corner School from Maldor will have to suffice. Magisters often manifest magical effects around their person--a deep, resonant voice, or floating a few feet above solid ground, or leaving glowing footprints; this could be handled by the Aura of the Imperator, and the Secret of the Iron Mind might be appropriate too (both are Elven species secrets from TSOY).

Oathsworn
Indefatigable servant of a sacred oath. The oathsworn take a vow (of any kind: serving the king, protecting your best friend, weeding the garden) and the power of the ritual sustains them without any need for food or rest, and gives them fanatical power and focus. These people, for some reason, avoid using tools of any kind and insist on accomplishing their missions with their bare hands. Technically speaking an oathsworn is anybody, from a knight to a serf to a sailor, who undergoes a specific Ritual of the Oath, and when the Oath is completed they lose their powrs. But in Arcana Unearthed they're presented as hand-to-hand fightin' men, who swear these oaths professionally, and when one mission is completed undergo the ritual again.
Primary - Any. Fighting for professional guys.
Secondary - Any. Illicit, for professionals.
Tertiary - Any. Craft, for professionals (they avoid using tools).
Oathsworn warriors have a lot of martial arts powers: you might want to look at the Zaru cultural skill Uptenbo. Taking the Secret of Imbuement gives their bare hands a +1 bonus to combat, and +3 when fighting in a cause directly related to the oath. Other options include the Secret of Throwing, the Secret of Knock-back, the Secret of Shattering, and the Secret of the Flying Leap. There should probably be a secret related to their ability to sustain themselves and ignore fatigue. Every oathsworn has the Key of the Mission (which can be renewed for professional types), and probably the Key of the Vow (to eschew the use of tools).

Runethane
Wielders of Pattern magic, a runethane is sort of a folk-wizard who specializes in buffing things up.
Primary - Craft (or Artistic).
Secondary - Artistic (or Craft), Priestly.
Runethanes have some simple Eldritch magic in addition to the Pattern magic they wield. (Pattern magic might be a version of the Zu magic words from the TSOY rulebook.) They should definitely take the Secret of Quality Construction, to represent inscribing magical runes on objects.

Totem Warrior
Chosen by animal-spirits, the totem warrior is at home in the wilderness.
Primary - Outdoors.
Secondary - Fighting, Illicit.
Totem warriors should take the Secret of (Animal) Familiarity and the Secret of (Animal) Companion (adapted from the Ratkin species secrets in the TSOY rulebook). The Secret of Swamp Lore (a Zaru cultural secret) might be adapted to other terrain types. The Panther Style skill (listed under Qek culture) could be adapted to the specific animal totem.

Unfettered
A swashbuckling scoundrel and wild man whose fighting style depends on instinct and raw cunning.
Primary - Social, with an emphasis on Duel... or Illicit, with emphasis on Assassination.
Secondary - Illicit (or Social), Fighting.
The unfettered are generally low-born types who are part swordsman, part thief. Several Secrets relating to swasbuckling combat might work well.

Warmain
Hulking tank-warriors, these are the heavily armored knights of the realm, who train in special war academies. They are skilled at all forms of warcraft.
Primary - Fighting.
Depending on the concept, Etiquette, Orate, and Rough Crafts might all be useful. Warmains should take the Secret of the Mighty Blow, and probably the Secret of Specialty (Battle - siege warfare). The Secret of Eleazar's Generalship (a Maldor cultural secret listed on this wiki) may be appropriate as well. Many other secrets relate to beating people up too.

Witch
More folk-magic, this time with certain themes: Iron, Sea, Wind, Wood, and something else I forget. Witches are sort of like untrained magicians who grew up wild.
Primary - I am still trying to figure out how witchery works.