System & Finder Shortcuts

Shortcut	Action
Cmd + Shift + N	New folder
Cmd + Delete	Move to Trash
Cmd + Shift + Delete	Empty Trash
Space	Quick Look preview
Cmd + I	Get Info (file details)
Cmd + D	Duplicate file
Cmd + Shift + .	Show/hide hidden files
Cmd + Opt + L	Open Downloads folder
Enter	Rename selected file
Cmd + Up	Go to parent folder

Screenshots

Shortcut	Action
Cmd + Shift + 3	Full screen capture
Cmd + Shift + 4	Area selection capture
Cmd + Shift + 4 + Space	Window capture
Cmd + Shift + 5	Screenshot/recording toolbar

System

Shortcut	Action
Ctrl + Cmd + Q	Lock screen
Cmd + Opt + Esc	Force Quit dialog
Cmd + Ctrl + Space	Emoji picker
Cmd + Ctrl + F	Toggle fullscreen
Ctrl + Cmd + Space	Character viewer (emoji & symbols)
Ctrl + Power	Restart / Sleep / Shut Down dialog

Window Management

Shortcut	Action
Fn + F	Tile window to fill screen
Fn + Ctrl + Left/Right	Tile to left/right half
Hold green button	Window tiling options
Cmd + Ctrl + F	Fullscreen toggle

Volume and Brightness

Shortcut	Action
F1 / F2	Screen brightness down/up
F10 / F11 / F12	Mute / Volume down / Volume up
Hold Shift + Opt + volume key	Fine-grained volume adjustment
Hold Shift + Opt + brightness key	Fine-grained brightness adjustment