Unity

Development Tools
Scene View Tools
Q Pan view (Hand tool) Win mac Linux
W Move tool Win mac Linux
E Rotate tool Win mac Linux
R Scale tool Win mac Linux
T Rect Transform tool (2D / UI) Win mac Linux
F Focus / frame selected object in Scene view Win mac Linux
GameObjects
CTRL+D Duplicate selected object Win Linux
+D Duplicate selected object mac
DEL Delete selected object Win mac Linux
CTRL+⇧ Shift+N Create empty GameObject Win Linux
+⇧ Shift+N Create empty GameObject mac
Play Mode
CTRL+P Enter / exit Play mode Win Linux
+P Enter / exit Play mode mac
CTRL+⇧ Shift+P Pause / unpause Play mode Win Linux
+⇧ Shift+P Pause / unpause Play mode mac
General
CTRL+Z Undo Win Linux
+Z Undo mac
CTRL+Y Redo Win Linux
+⇧ Shift+Z Redo mac
CTRL+S Save scene Win Linux
+S Save scene mac
CTRL+⇧ Shift+S Save project (all assets) Win Linux
+⇧ Shift+S Save project (all assets) mac