Interesting builds based around fire.

[The Pale King]

So if you want to do a fire build there are a couple really obvious ways, Flame Oracle, Flame Shaman, Orc/Dragon crossblooded Sorcerer... But I am looking for some more interesting character builds based around the element of fire. An elemental knight Suli could be really cool, but it is unfortunate that they get that -2 int.

[Secret Wizard]

Goblin Rogue, use Fire Hand to get proficiency with torches (and a glorious +1 to attack)...

Burn! Burn! Burn! to deal 1d4 extra damage whenever you hit.

Add Makeshift Scrapper, get Throw Anything to toss torches around, Catch Off-Guard to make any disarmed enemy flat-footed against your torch hits...
Possibly get Disarming feats to take advantage of that. Later on, Supernatural Improvisation will increase the damage you deal with torches too!

BUT THAT'S NOT ALL!

Add Underground Chemist to add sneak attack damage and your Intelligence bonus to splash weapons!

Then, pick the Bomber Rogue Talent to throw fire bombs too! You get all the benefits from Fire Hand and Burn! Burn Burn! as well.

BUT ITS NOT OVER YET!

Add on top of that the Scout archetype and enjoy easy sneak attacks as you charge around and toss torches towards your enemies.

If you are using Unchained, you get Dexterity to damage to melee torch attacks too, so you can just base yourself on DEX-to-damage with melee torch hits, and INT-to-damage for ranged splash weapon hits.

[The Pale King]

That build seems absolutely ludicrous and amazing. I love it.

[Dafydd]

Only thing I can tack onto Secret Wizard's build is this:

Secret Wizard wrote:

Catch Off-Guard to make any disarmed enemy flat-footed against your torch hits...

Possibly get Disarming feats to take advantage of that.

Burning Disarm

Either the foe takes fire damage, a strong amount too (capping at 5d4) OR they are disarmed. Only works if the foe is using a metal weapon, but if they are...

How to get it quickened is the big question however, as then you could full attack, gaining sneak attack on each torch hit. (Major Magic Rogue Talent, plus Quicken Spell Like Ability is an option, but requires GM signing off on using a monster feat, and does not come online till 10th level, at least)

[Gregory Connolly]

A bard with a sorcerer dip and Fire Music would play pretty different than your normal blaster.

Bomb focused alchemists can be rather effective at playing with fire, used to be common years back but I haven't seen any lately.

An ifrit paladin of Sarenrae could do pretty well, with or without dipping into dawnflower dervish.

[Silent Saturn]

Ifrit barbarian. Take all the "elemental" rage powers, to give yourself flaming burst weapons, fire resistance, and the ability to absorb fire damage and spit it back as a breath weapon. For extra fun, take Exotic Weapon Proficiency (battle poi).

The only levels of Summon Monster that don't have an elemental on them are I, III, and IX. I has the fire beetle, however, and III and IX can just get you 1d3 of the previous level's elemental. Summon Monster V can get you a salamander, as well. A summoner could easily focus on summoning fire elementals and fire-themed creatures, and maybe give his eidolon the "energy" evolution to make one of its attacks do fire damage.

[Darigaaz the Igniter]

I still like the blockbuster wizard build, myself.