Below is a list of all the available elements in the Fire group in Doodle God across all 4 episodes.

Episode 1:
Coal
Fire
Lava
Oil
Plasma
Saltpetre
Sulfur

Episode 2:
Coal
Fire
Lava
Oil
Plasma
Saltpetre
Sulfur
Sun

Episode 3:
Coal
Fire
Lava
Oil
Plasma
Saltpetre
Sulfur
Sun

Episode 4:
Fire element group does not exist in episode 4.