option + command + space = To open finder
command + space = spotlight
command + shift + 4 = screenshot
Shift + Command + N: Create a new folder.
Shift + Command + Delete = Move selected file or folder to trash
Command + q = immediate quit current app
Command + Left Arrow = Move the insertion point to the beginning of the current line.
Command + Shift + i (in safari) = Send current page link to mail
Command + Option (in Safari)+ L = Downloads folder