a-z keyboard focus mode, click the a-z button on the (inner) edit window (not the A-Z button clip list or groups). Keyboard focus turns the entire keyboard into one stroke commands, this is hands down the best and fastest way to work in Pro Tools.
Here are a few of my favorite key commands.
R T - Zoom out and in
E - Zoom toggle
P ; - move selection/cursor up and down
L ‘ - move left and right through regions
D - Fade to start
G - Fade to end
A - trim from front of file from selection
S - trim from back of file from selection
ZXCV - undo, cut, copy, paste
B - separate
N - insertion follows playback or not
Q - view front of selection
W - view back of selection
– (minus key) - toggle waveform and volume view