Pyromaniac (Arson).
A "harmonicanist" is what a person who plays the harmonica is called.
A person who plays Scrabble is called a Scrabbler. (unofficially)
pyromancer
A person who fights fire is called a fire fighter.
A drummer or percussionist plays the drums.
harpist
An organist
a cymbalist
Guitarist
a baritonist
guitarist
A saxophonist.