For unrelated reasons, I was making a list of Sor/Wiz spells with the [Fire] descriptor. Naturally, this is limited to sources that I actually own. Here it is:
1st: burning hands, lesser fire orb (T&B)
2nd: Aganazzar's scorcher (FRCS 66), body of the sun (MotW 84), combust (MoF 85), flame dagger (MoF 94), flaming sphere [, pyrotechnics - not a [Fire] spell, but should be,] scorching ray
3rd: fireball, flame arrow, flashburst (FRCS 70)
4th: explosive cascade (MoF 93), fire shield, fire trap, wall of fire
5th: firebrand (MoF 94)
6th: fire spiders (MoF 94)
7th: delayed blast fireball
8th: incendiary cloud
9th: meteor swarm
Unlabeled spells are from the Player's Handbook.
FRCS = Forgotten Realms Campaign Setting
MoF = Magic of Faerun
MotW = Masters of the Wild
T&B = Tome and Blood
You could also use limited wish or wish to cast non-Sor/Wiz [Fire] spells, such as firestorm (shapeable, 20d6 damage cap) or fire seeds.