Using Greenie grounding connectors
Green wirenuts with a hole in the tip are stupid.

You're not supposed to stick one of the wires in the top. You're supposed to stick all the wires in the bottom, and one of the wires is 9" longer than the others and is supposed to stick through to let you ground one more thing. 

What does this mean? You're supposed to strip about 18" of Romex sheath off, and then cut 9" off all wires but the ground wire.  So you are wasting nearly a foot of Romex.  The logic is you are supposed to use the cutoff wires as pigtails later.  Meh.

What is pictured is a perfect use case for it, though, as it already has 6 ground wires incoming and 3 switches to also deliver grounds to.  Without tricks, you'd need to put 9 grounds under a wirenut, (plus one for the box). They don't make 10-wire nuts, so you'd need to be split into 2-3 wirenuts with a pigtail between them.  This latter approach is exactly what I would do.