General terms:
* Fire
* Flame
* Blaze
* Ember
* Ash
* Smoke
* Heat
* Combustion
* Ignition
* Kindling
* Fuel
* Pyrotechnics
Intensity and Color:
* Fiery
* Flaming
* Scorching
* Glowing
* Incandescent
* Flickering
* Smoldering
* Burning
* Roaring
Effects:
* Charred
* Seared
* Singed
* Scorched
* Smoked
* Ashen
Related to fire-making:
* Match
* Lighter
* Kindling
* Tinder
* Fireplace
* Stove
* Chimney
Metaphorical:
* Fiery (passionate)
* Burning (intense)
* Incinerating (destructive)
* A burning desire (strong yearning)
* A fire in the belly (determination)
Jobs:
* Firefighter
* Fire marshal
* Arson investigator
Places:
* Fire station
* Inferno
* Crematorium
Other:
* Fire alarm
* Fire extinguisher
* Fire escape
* Fire hydrant
* Firebreak
Let me know if you want more specific categories or examples!