Mac (macos) startup keyboard boot sequence combinations

A sequence of keyboard key combinations are really useful when doing troubleshooting on your Mac computers (Macbook Air, Mini, iMac or Macbook pro's),

You need to press and hold these key combinations immediately after you press the power, you can use them even after your Mac reboots. Make sure you keep holding the keys until you see the described behavior.

• C → boot from CD - gone are the CD-Rom days though :)
• T → To boot in target disk mode.
• D → To boot in Apple Diagnostics utility.
• N →To boot from NetBoot server
• Command (⌘) + R → To start macOS Recovery System.
• Option (⌥) + Command (⌘) + R → To start macOS Recovery mode over the Internet.
• Shift + Option (⌥) + Command + R → Start macOS Recovery mode over the Internet.
• Option (⌥) → This will display the Startup Manager
• Alt → This will display the Startup Manager. You can choose from various options such as startup disk or volume.
• Option (⌥) + Command (⌘) + P + R → Reset NVRAM or PRAM.
• Shift (⇧) → To Startup in safe mode.
• Command (⌘) + S → To boot in single-user mode.
• Command (⌘) + V → To boot in verbose mode.
• Eject (⏏) → To remove/eject media, such as an optical disc.
• F12 → To remove/eject media, such as an optical disc.
• Mouse Button or Trackpad Button → To remove/eject media, such as an optical disc.