I use the left control key on a full sized desktop keyboard as my "palm" key (I press it with the heel of my left hand). Being an Emacs user, it made my left pinky so much happier.
This doesn't work on laptops because of the low profile keys, so I stack some 3M "dual lock" squares on the control key to raise the profile. They can be removed (except for the one glued to key) when I need to close the laptop.
The Emacs keyboard chords were worked out on keyboards that had the Control keys nearest the Space bar - the intention was that you would use your thumbs to press the Control and Meta keys. Turns out this is really useful not just for Emacs but for any program that uses Control modifier shortcuts. I have not had any hand pain after doing this key remapping on my systems:
Similarly, I use the same bindings I mentioned above on my laptop keyboard, and there I have the right command key bound to control. Since it's right next to the spacebar I can easily hold it down with my thumb while using other keys to move around.
This doesn't work on laptops because of the low profile keys, so I stack some 3M "dual lock" squares on the control key to raise the profile. They can be removed (except for the one glued to key) when I need to close the laptop.