Shortcuts.

Tools Shortcut Name	Shortcut Key
Add Shape	+
Subtract Shape	-
Preserve Transparency (toggle)	/
Decrease Brush Size	[
Increase Brush Size	]
Decrease Brush Softness by 25%	Shift+ [
Increase Brush Hardness by 25%	Shift+ ]
Previous Brush	<
Next Brush	>
First Brush	Shift+ <
Last Brush	Shift+ >
Tool Opacity 10% → 100%	1 → 0
Flow / Airbrush Opacity 10% → 100%	Shift+1 → 0
Path / Direct Selection Tool	A
Brush / Pencil / Color Replacement Tool	B
Crop Tool	C
Default Colors	D
Eraser Tool	E
Cycle Screen Modes	F
Gradient / Paint Bucket Tool	G
Hand Tool	H
Eyedropper / Sampler / Measure Tool	I
Spot Healing / Healing / Patch / Red Eye	J
Slice Tool	K
Lasso Tool	L
Marquee Tool	M
Notes / Audio Annotation Tool	N
Dodge / Burn / Sponge Tool	O
Pen / Freeform Pen Tool	P
Standard / Quick Mask Mode	Q
Blur / Sharpen / Smudge Tool	R
Clone / Pattern Stamp Tool	S
Type Tool (Vertical / Horizontal)	T
Shape Tool	U
Move Tool	V
Magic Wand Tool	W
Switch Colors	X
History / Art History Brush Tool	Y
Zoom Tool	Z
Hand Tool (toggle)	Space
Zoom In (toggle)	Ctrl+Space
Zoom Out (toggle)	Alt+Space
Cycle Path / Direct Selection Tools	Shift+A
Cycle Brush / Pencil / Color Replacement	Shift+B
Cycle Eraser Tools	Shift+E
Menubar (show / hide)	Shift+F
Toggle Gradient / Paint Bucket Tools	Shift+G
Cycle Eyedropper / Sampler / Measure	Shift+ I
Cycle Spot / Healing / Patch / Red Eye	Shift+J
Toggle Slice / Slice Select Tools	Shift+K
Cycle Lasso Tools	Shift+L
Toggle Rectangular / Elliptical Marquee	Shift+M
Toggle Notes / Audio Annotation Tools	Shift+N
Cycle Dodge / Burn / Sponge Tools	Shift+O
Toggle Pen / Freeform Pen Tools	Shift+P
Cycle Blur / Sharpen / Smudge Tools	Shift+R
Toggle Clone / Pattern Stamp Tools	Shift+S
Cycle Type Tools (Vertical / Horizontal)	Shift+T
Cycle Shape / Line Tools	Shift+U
Toggle History / Art History Brush	Shift+Y
Airbrush (Brush Tool)	Alt+Shift+P