Coil packs 6,7,8 aren't working. Does anyone know the fuse location or have any other suggestions? Thanks in advance.

 

Are the coils not working, or are you getting a misfire at those cylinders? Misfire can be much more than coil pack. I can't help with the fuse location.

I know it would be really low odds of all 3 going bad, but have you inspected them? Swapped them around the engine with other coils to see what happens? Replaced them with new coils?
Pull them and inspect the spark plug holes for excess moisture. Is there a coolant leak? Did you plow through water recently?
Inspect the wiring harness. Are there squirrels, mice or rats that might have chewed it? Had any mechanical work done recently that might have pinched the harness?

 

All 8 COPs work off the same fuse. So, you're likely looking for a bad splice in the wiring harness where cylinders 5-8 come together.