The ones I love are Shift-iand Shift-o – go to in or out, x – Mark Clip, Option-A that was mentioned above, Shift-X and Shift-V – Ripple Copy/Paste, v, u to select an edit and toggle between trim modes and then square brackets to do the trim, e – Extend Edit, q to toggle between Viewer and Canvas, f – Match Frame, F11 – Replace, Shift-F11 – Fit to Fill.
A quick way to trim away the head or the tail of the clip up or down of your current frame is x, i for tail or o for head and the Del or Shift-Delete.
When you are lost on your timeline – zoomed in on selection instead of the playhead just type Right or Left Arrow once.
When you need Slug but some video is in the Viewer Command-W Command-1
Autoselect shortcuts are very helpful too, much better than track targeting ones though I use either all the time.
I hate Command-Shift-A to Deselect All and remap it back to Command-D immediately