One of my favorites is one that's in PT by mistake (ie: a programming error). It only works on Mac as well.
Shift + Opt + 3 creates a consolidated selection. However, if you add Ctrl to it before you hot 3 then it will fill your selection with a 1K -20dB sine wave. Which is perfect for making 2pops and 3beeps.
I have other favorites, but this one stands out as a bit unique.
-----Everything below was edited in-----
Here's some added one's that I use the most. Keep in mind I typically work in Command Focus A/Z mode.
R and T in command focus mode = Zoom Out+In
CMD + to toggle Edit/Mix window
Shift + CMD + N = New Track (CMD + Arrow keys add additional shortcuts in track creation window like changing channel and track types, Shift + CMD + Up/Down Arrows = Add or Subtract a new entry line)
B = Separate Region
CMD + T = Top & Tail (Trim region start and end to selection)
CMD + F = Fade Utility + D & G Fade to start/end/ Tools.
Option + C = Clear Clip Indicators
Shift + Option + 3 = Consolidate
Shift + Spacebar = Halfspeed Playback or Halfspeed Record.
Shift + CMD + U = Select Unused.
F = Focus Cursor
Option + F = Focus Selection to screen width.
~ = Toggle Editing mode
Tab, Shift Tab, Option Tab and Shift Option Tab all for navigating between regions and making selections.
P and ; for moving the cursor/selection up and down tracks
CTRL + Click and Drag to retain time position while moving regions up and down tracks.
Option = Option Does to All
Shift + Option = Does to Selected
CMD + D = Duplicate at end of Region
Option + Click and Drag = Copies and Drags Copy to New Location
Option + Ctrl + Click Drag Up or Down will Duplicate Region Vertically with Time Constraints.
Shift + , = Drop Sync Point on Region.
Control + Click = Snap Region Start to cursor
Control + CMD + Click = Snap Region End to cursor
Shift + Ctrl + Click = Snap Sync Point to Cursor
Opt + Ctrl + CMD + Down Arrow to fit tracks to window height.
E = Explode
I could go on and on. I'll stop here though.