My main class in FF14 the Summoner is pretty unique for that class-typically Summoners either focus on white mage or black magic in most ff games (Rydia or Yuna for example) on top of their summons.
Arcanists (Base Class for Summoner and Scholar) can summon two types of Carbunkles (a caster or a tank type), the Scholar can summon a healing Sylph or a Support Sylph and Summoners can summon a Ifrit-Egi (Close range DPS), a Titan-Egi (Tank), or Garuda-Egi (Ranged DPS).
In 14 a summoner siphons a portion of a Primal's (The Summons of FF14's world) and creates an Egi, a familer like creature that acts as a Pet in battle. Their main spells are mostly poison like effects that all stack with each other for massive damage over time on top of their summon constantly attacking as well.
Ruin - Deals light to moderate damage to one foe (short cast time)
Ruin II - Deals larger damage has no cast time but costs more MP (Also Blinds)
Ruin III - Costs nearly nearly 40% of your MP but deals high damage (A special mechanic lowers it to more reasonable costs however)
Bio - Does damage over time (think Poison)
Bio II - Does damage over time (Stacks with Bio)
Miasma - Does damage over time (Stacks like the others) and inflicts several debuffs like slow and heavy.
Miasma 2 - Does damage over time to enemies at point blank range also reduces the target's ability to recover HP for a bit.
Virus - Debuffs target's Strength,Dexterity,Intelligence,and Mind for about 10 seconds.
Tri-Bind - Deals low damage and puts heavy on the target
Tri-Disaster - Inflicts Bio+Bio II+Miasma all at once (has a decent cool down time)
Shadow Flare - Lays down an Area of effect bubble that damages any enemy standing in it over time.
Their main mechanic however is a skill called Aether Flow that gives them three stacks of this status that can be spent on powerful spells. It also recovered about 50% or so of the user's MP at once (has a minute cool down)
Bane - Inflicts all Bio/BioII/Miasma/MiasmaII effects onto all other targets nearby at lesser effect.
Fester - Inflicts massive damage depending how many of the Summoner's damage over time spells are in effect.
Energy Drain - Deals moderate damage and siphons that damage into HP and MP
Pain Flare - Deals moderate damage to all enemies around the target
Dreadwyrm Trance - Once you spend all three stacks of Aether Flow you can use this to summon a portion of Bahamut's power and gain a 10% increase to all magic damage on top of reducing the cost of Ruin III to a reasonable amount for about 12 seconds.
Death Flare - At any time during the Trance you can use this massively powerful AOE spell that drains all remaining time form the trance (Although you can spam Ruin III till the last second then cast it
)
Pretty different than most Summoners in the franchise. I really like the focus it has rather than just out right black or white magic. I guess Ruin is a black magic spell though?
Edit: Oh yeah forgot the Arcanist/Summoner and Scholar have a healing spell called Physick that is only really effective when used by a Scholar (as they are healers with DoT attacks), and Resurrection a costly revive that allows you to bring back party members in battle right away while White Mages need to get a trait that lets them use Raise in battle.