[narwally]

And the Mac kill ring is separate from the clipboard so that means you can have two things copied at once and insert them with separate keybindings. Unfortunately the kill ring only contains a single element, so has no history.

some other useful ones are C-h/C-d (backwords/forwards delete), C-o (insert line), and the main Emacs movement keys C-n, C-p, C-b, C-f. Remapping Capslock to be a second Control makes using these regularly much more natural. Karabiner is a good app for easily remapping keys on macOS.