Phew, this is taking longer than I thought but I'm nearly done now.
Here we're going to be going over the different versions of Arcane Backgrounds for Athas: Elementalism, Magic and Psionics. Templars would qualify as well but seeing as they're meant to be NPCs and their power depends on the favor of the sorcerer kings I'm not going to provide PC stats for them. If you feel the need it's easy enough to give them the Miracles AB from the core SW book. But here's all the rest:
Arcane Background (Elementalism)
Arcane Skill: Channeling (Spirit)
Starting Power Points: 10
Starting Powers: 2 plus Elemental Manipulation
Elementalists are those who can channel raw elemental forces. Their powers are based on a spiritual affinity with a given element and elementalists often take the role of religious or spiritual advisers. When choosing this arcane background characters must select one of the four elements that they are particularly aligned with which determines their power's trappings and what powers they may learn. Elementalists cast their spells through simple rituals that require them to be able to speak freely and make basic gestures.
Each elementalist automatically begins with the elemental manipulation Power appropriate to their chosen element as well as two additional Powers. They may select powers based on the lists below. Even for their "universal" powers you should alter the trappings to coincide with the appropriate element. Powers marked with an * are found in the Fantasy Companion book for Savage Worlds.
Universal powers: Barrier, Burst, Detect/Conceal Arcana, Dispel, Divination*, Environmental Protection, Healing, Obscure, Smite, Summon Ally (elemental only)*
Air: Deflection, Fly, Havoc*, Intangibility*, Invisibility, Pummel*, Speed, Stun.
Earth: Armor, Boost Trait (Strength and Vigor), Burrow, Entangle.
Fire: Armor**, Blast, Bolt, Damage Field, Draining Touch (heat stroke)*.
Water: Boost/Lower Trait, Draining Touch (dehydration)*, Greater Healing, Succor*
**only protects against cold or fire, but double the armor bonus.
Edges: Elementalists can select the Champion or Holy/Unholy Warrior edges using their AB in place of Miracles (renaming the edges to (Element) Champion and Elemental Warrior). Champion provides a bonus to damage against beings associated with the elementalists opposed element, and provides it's bonus to toughness against effects created by the elementalist's chosen element (so a fire elementalist would inflict +2 damage against supernatural creatures associated with the element of water and would have +2 toughness against supernatural beings or powers associated with the element of fire). Elemental Warrior would allow the elementalist to repulse supernatural beings associated with the elementalist's opposed element.
Elementalists do not suffer any consequences when rolling a 1 on their Channeling skill.
Arcane Background (Magic)
Arcane Skill: Spellcasting (Smarts)
Starting Powers: 4
Starting Power Points: 15
Magicians in Athas fuel their powers by draining the life energy from the earth beneath their feet and the plant life around them. However, some do learn to take only what is necessary and return the rest. To cast their spells mages must use a variety of arcane words and gestures (many use Stealth to conceal their spellcasting).
Mages may learn all Powers except for Healing, Greater Healing, and Succor.
Defiling: When a mage casts a spell the energy of the land is drawn to him, creating a thin layer of black ash on the surface of the ground. In most environments this creates a clear circle of defiled land with a radius equal to 1" per power point spent by the mage (the Wizard Edge can reduce this but even if the spell's cost is reduced to 0 it still defiles at least 1"). Environments that are particularly lush and rich with life may cut this radius in half, while particularly lifeless areas will double it. If a second spell is cast within a defiled area it increases by the appropriate amount.
Backlash: Magic is dangerous and somewhat unstable, on a roll of 1 on the spellcasting skill die the mage is Shaken. This can cause a Wound.
Edges: Mages can use the Soul Drain edge to prevent defiling, but most who wish to avoid defiling the land learn the Preserver edge.
Preserver (Novice, AB (magic), Spellcasting d6+, Spirit d8+)
You have learned how to perform magic without inflicting permanent harm on the planet. When you use a power you may choose whether to defile or use this edge. Casting spells without defiling increases the PP cost by 1. Exceptionally lush areas remove this extra cost while areas that are very barren (or already defiled) increase it by 2.
Arcane Background (Psionics)
Arcane Skill: Psionics (Smarts)
Starting Power Points: 10
Starting Powers: 3
Psionicists are the most common and well-known power users on Athas. Almost everyone has some psionic talent and there are entire schools devoted to enhancing one's psionic abilities. Unlike other arcane backgrounds Psionics requires no special rituals or words of power, merely concentration and focus.
Psionicists can choose from the following powers, many of which may have a variety of different trappings depending on how the particular psionicist manifests the ability. Powers which affect other powers (such as Detect/Conceal Arcana and Dispel) only function against other Psionic powers when manifested by a Psionicist but psionic powers are likewise unaffected by versions of those powers used by a non-psionic spellcaster.
Psionic Powers: Armor, Barrier, Beast Friend, Blast, Blind*, Bolt, Boost Trait (self only, Lower Trait, Burst, Concentrate*, Confusion*, Deflection, Drain Power Points (psionic only)*, Detect/Conceal Arcana, Dispel, Draining Touch, Fear, Greater Healing (self only), Havoc*, Healing, Invisibility, Legerdemain*, Light, Pummel*, Puppet, Quickness, Sluggish Reflexes*, Slumber*, Smite, Speak Language, Speed, Stun, Succor*, Telekinesis, Teleport,
Psionic Limitations: Although psionics are widespread and potent they rarely match the raw power of magic. Most Psionic powers should have some trappings that limit them in some way in order to perform optimally (as presented by the basic power). For example, take the Bolt power. A psionicist might use Bolt to hurl objects at his opponents (inflicting standard damage at the normal cost for Bolt) but if he doesn't have anything to throw he's unable to use it. A version of Bolt that simply punches an opponent with telekinetic force should have either an increased cost (perhaps an additional power point per bolt) or do less damage (damage dice of d4's rather than d6's). At the GM's option some Powers (Telekinesis for instance) may operate at peak efficiency for psionicists automatically.
Brainburn: Psionicists who roll a 1 on their Psionics skill die lose 1d4 power points in addition to the cost of the power.
The main thing that separates Dark Sun from other settings is the hostile environment. Characters must drink a gallon of water every day in order to remain hydrated in the intense heat. If they cannot drink at least that much water then they must make Vigor rolls every 4 hours (keep in mind that it's significantly cooler at night, so normally that's a maximum of 3 Vigor rolls a day). A failure means the character suffers a point of Fatigue. If a character becomes Incapacitated due to this fatigue they have to make a second Vigor roll or suffer a permanent reduction of one die type to Strength and Smarts.
There are several modifiers to this roll:
Water: if the character cannot drink at least half a gallon they suffer a -2 penalty. If they get no water it is a -4 penalty. This is in addition to the effects of dehydration.
Temperature: The average temperature of Athas is around 120 degrees and this inflicts a -3 penalty to the Vigor roll, particularly warmer or cooler areas adjust this up or down by 10 degrees. Temperatures below 90 do not require a roll.
Resting: +1 to the roll if the character stops any physical activity
Shade: +1 to the roll if the character can stay under significant shade.
Using Survival in the deserts of Athas is particularly tough. Using Survival in the deserts is at a -2 penalty. Success finds the normal amount of food but only half the normal amount of water (so a success finds half rations for one person, a raise finds half rations for five or full rations for 2).