@Sebecloki: Knowledge of Final Fantasy's fluff isn't required. It will definitely aid in your appreciation of the game if you have some though. Most of the information you need is going to be in the exposition and setting drop.
Final Fantasy doesn't have traditional clerical classes that require devotion apart from the Cleric. There are some with ties to sacred or profane energies- such as the White Mage, Paladin, Dark Knight, and such- but devotion to the gods is not the primary way to gain power in the Final Fantasy universe. Magic is magic in this universe and has no distinction based on the source, only what type it is. If you're familiar with Magic the Gathering, it's similarly divided into color-coded concepts here by and large.
Black Magic is destructive or debilitative in nature and ranges from elemental spells to devious tricks like poison or draining HP from enemies to restore your own.
White Magic is mostly supportive in nature and consists of healing, buffing, and the occasional debuffing, with only a select few high level holy spells being used for damage.
Blue Magic is strange in it's own way because you learn it from enemies who use it and provides a wide range of spells, many of which are only useful in specific scenarios.
Red Magic combines Black and White Magic and is sort of a generalist approach to magic, with some unique spells thrown in the mix depending on the game like spellblade effects in XIV.
Green Magic- now known as Time Magic- focuses on a variety of time and space-flavored buffs and debuffs like Haste, Slow, and Stop, plus things like Comet, Gravity Ball, Teleport, and similar spells.
Astrologian Magic blends healing spells, utility spells, some divinations, and a select few damage spells like Sunburst.
Bards don't have magic per se, but their Bard Songs function as spells in everything but name. Bards are capable of massive buffing and have a smattering of other types of spells. Not too much different than the Pathfinder Bard if you really think about it.
Dark Knights and Holy Knights are essentially Antipaladins and Paladins and have spell selections to match. Dark Knights have a great deal of shadow damage-based spells, personal buffs, and a few summon spells. Holy Knights have heals, buffs, and holy damage-based spells.
Druids and Geomancers have about what you could expect and are very close to the Pathfinder Druid with what kinds of spells they have access to. They're nature mages with a broad swathe of potential spells.
Illusionists have a spell list consisting of, well... illusions.
Necromancers specialize in spells that deal shadow damage, status effects like poison and zombify, and instant death effects. Instant death effects aren't as strong in FFd20 because most "bosses" are flat-out immune to them, just like in the video games.
Summoners are very similar to their Pathfinder iteration, focused on conjuring creatures, gear, et cetera, and have a smattering of other things like elemental and utility spells.
There are a range of other magical powers that resemble Spheres of Power spherecasting, Path of War maneuvers, and what have you, but those don't function using the MP system.
Based on your stated preferences, I'd suggest looking into the Bard, Thief, White Mage, Astrologian, Chemist, Cleric, Dark Knight, Necromancer, Time Mage, Dancer, and Ninja. There are quite a few archetypes and some are modeled on existing Pathfinder archetypes, so you will probably be able to find something that suits your tastes.
Clerics get very different spell lists and class features based on what Deific Order they belong to. Just be aware that Clerics are not as bland as they first seem because of that design choice. Link for Deific Orders.
@Storm Dragon: There are absolutely Blue Mages in the FFd20 system and I always aim to give players access to as much Blue Magic as I can. So you won't run into the normal problem of a GM being stingy with opportunities to learn new Blue Magic.