Undo

Command + Z

Ctrl + Z

Redo

Command + Y

Ctrl + Y

Fade

Command + Shift + F

Ctrl + Shift + F

Cut

Command + X

Ctrl + X

Copy

Command + C

Ctrl + C

Copy merged

Command + Option + C

Shift + Ctrl + C

Paste

Shift + Command + V

Shift + Ctrl + V

Paste in place

Command + V

Ctrl + V

Fill

Command + F

Ctrl + F

Free transform

Option + Command + T

Alt + Ctrl + T

Preferences General

Ctrl + ,

Preferences Brush tracking

Shift + Ctrl + ,

Preferences Customize Keys

Ctrl + Alt + ,