Those are far from all the shortcuts. Sometimes I'm using a photoshop shortcut and it accidentally works (but not all), so a complete list would be nice.

I found the list below in this thread click using search ( whoops, forgot that before ^^; ) and I'll now be updating it when I find new ones.

Undo:  Ctrl-Z
Redo:  Shift-Ctrl-Z 
Brush Size: [ ]
Zoom Out:-
Zoom In:+
Zoom 100%: Ctrl 0
Brush opacity: 1 through 0,
Image scrolling:  SPACE and drag with the left mouse button .

Cut: Ctrl X
Copy: Ctrl C
Copy Merged: Ctrl, shift, C
Paste: Ctrl V
Select All: Ctrl A
Deselect: Ctrl  D

Duplicate: Ctrl, shift, D
Merge layer down: Ctrl E

Clear: delete
Fill: Ctrl F
Toggle Pallet: Tab

Grid  Ctrl G  on and off