Hide Current Application
⌘ Command + H
Hide All Window
⌘ Command + ⌥ Option + H + M
Change Language
(Open Keyboard preference, enable use the Caps Lock key to switch to and from ABC)
⇪ Caps Lock
Markdown Preview
⌘ Command + K -> V
Duplicate Line
⌥ Option + ⇧ Shift + Arrow Down
Open Terminal
⌘ Command + J
Stop Running Process
⌃ Ctrl + Z