I have two builds that I really like playing:

Sage DPSer with some utility, I deal about 6k damage per hit with multi hit spells like Leaf Cutter while having heals, buffs and a bunch of debuffs:

Concentrate (Reraise 8, Crit Rate Up 8) Aqua Breath (Water 1, Combo Factor 1, Range Factor 1, Burn 2, Poison 2, Blind 3, Paralyze 3, Freeze 3) Imperil (Ele Res Down 12, Slow 1, Stop 1, P-Def Down 1, M-Def Down 1) Curaga (Remove Ailments 5, Regen 2, Haste 2, Create Image 2, Reflect 2, P-Def Up 1, M-Def Up 1, Ele Res Up 1) Leaf Cutter (Multi-Hit 2, Combo Factor 1, Link: Magnetic Storm 1, Resonance Factor 1, Trance Boost 1) Thundaga (Multi-Hit 2, Combo Factor 1, Area of Effect 1, HP Power Factor 1, Resonance Factor 1, Trance Boost 1) Thunder (Multi-Hit 2, Combo Factor 1, Area of Effect 1, Resonance Factor 1, Trance Boost 1, Link: Thundara) Thundara (Multi-Hit 2, Combo Factor 1, Area of Effect 1, HP Power Factor 1, Resonance Factor 1, Trance Boost 1, Link: Thundaga)

Time Mage buff support. I run around throwing out buffs and occasionally healing people and using Slow for the debuffs I have it mutated with. I put Invisibility on Haste because being invisible allows my AP to recharge quickly as if I wasn't in combat as long as I don't use Slow while invisible to deactivate it:

Chronos (Reraise 1, Reflect 2, Image 2, Faster Cooldown 1), I simply haven't bothered mutating this. Reraise (Area of Effect 3) Shell (Image 8, Reflect 8) Quick (Image 1, Reflect 1, Area of Effect 1) Haste (Invisibility 16) Slow (Duration Up 2, Ele Res Down 8, Freeze 1, Stop 1, Paralyze 1, Blind 1, Poison 1, Burn 1) Protect (Image 8, Reflect 8) Cure (Remove Ailments 5, Regen 2, Haste 2, Image 2, Reflect 2, P-Def Up 1, M-Def Up 1, Ele Res Up 1)