Personal favorites are C-r to search back in history and C-x C-e to edit the current command line in an external editor.
I use "yank-last-arg" most often, which is M-. by default.
$ mkdir abcd
$ cd <M-.>
In reading the manpage for Bash, which doesn't have this function, I've just found "history-search-backward", which searches through history to find commands based on what you've already typed. That will come in useful!
$ bind '"\er":history-search-backward'
$ bind <M-r>
These functions are all listed, with explanations, in the Bash and Zsh manpages.
Edit: As I see from another comment, a binding for "history-search-backward" to the Page Up key is in /etc/inputrc on Debian and derivatives.
if [[ $- == *i* ]]
then
bind '"\e[A": history-search-backward'
bind '"\e[B": history-search-forward'
fi
What's the point to type a half-command and then replace input line with one from history if I press up? That somewhat resembles ugly cmd.exe, which every windows user imagines when someone says 'cli'.
This is the shortcut to first learn when starting living in the command line.