IGMF stands for "I got my frags". Usually used in context of
multiplayer FPS games.
In games like
Rainbow Six Siege or CS:GO, where there is same amount of people in your and enemy team. There is a funny analogy that If everyone gets one frag(kill), the team will win. And when the team looses,
the person who got a kill be like "I got my frags".
This phrase is usually used in a sarcastic manner. People are aware that the analogy of 'if everyone gets one frag then their team wins' is flawed.