For cover band gigs I have a binder that I put on the floor between the base of my mic stand and my vocal monitor. It has a divider for each letter of the alphabet. Songs are in alphabetical order (obviously). I have a few hundred songs in the binder, one song per page. What's written on each page varies depending on the song. Most pages have chord names, bar lines, repeat signs, etc. Some have the lyrics with chord names over the words if I'm singing the lead vocal part.
For gigs where I'm playing original music, I memorize the songs.
For gigs where I'm playing original music, I memorize the songs.