I discovered something awesome. With the new picking technique I adopted a few months ago, I can pluck strings with my index finger without altering my grip on the pick.
The tip of my right index finger is exposed from behind the pick, protruding on the side closer to the bridge. All I have to do is change the angle of my hand, and I can substitute a finger pluck for a picking upstroke.
Why would I want to do this? I can already use my middle, ring, and pinky fingers to pluck notes. But I get more force, control, and accuracy when using my index finger, especially when coupled with my thumb, squeezing them together. It's much like the popping employed in slap bass technique. It's a great blues/funk sound on a Strat, and it's a welcome addition to my aggressive style. There's no way to play a note harder than pulling it back and letting it rip like a bow and arrow.