No not an official one. There used to be some Thunder themed raps but they were all crap so now DJ Boom just plays whatever. Sometimes, well a lot of the time, they come out to to TI "Bring'em Out" when they are coming out of the tunnel and bring introduced; a lot of Lil Wayne and DJ Khaled radio edits. KD and James Harden have a crapass rapper named Privaledge they are always hyping up who made a Thunder rap and they played it like 2wice then scrapped it
Besides being garbage, like most rappers, he just couldn't stay on topic without the swearing, drug and sex references.
But short answer, no there is no fight song.
Pregame prayer, national anthem, road team intro, home team intro, basketball