This is more a discussion of covers than the covers themselves. I won't reprint the words here, or even take the time to list them exactly. I know what covers I know, of course, but here, on this site, let's speak more in generalities. First and foremost, I cover what I can sing. If I really want the song, and I struggle with the vocals as per the original, I'll adjust for my voice. I need to feel the message, agree with the words, ideas, and concepts being presented.
Not every song is going to work at every venue, but I've collected somewhere around 70 cover songs ranging from Woody Guthrie in the 1940s, a heavy emphasis on the folk revolution of the 60s and 70s (Bob Dylan, Grateful Dead, Simon & Garfunkel, etc.), and many popular rock songs from the same era through the 90s. I don't cover a lot of female vocalists, but they aren't off the table. I do a fine rendition of Gloria Gaynor's "I will Survive" and a Melanie Safka tune, "Look what they've Done to my Song." Admittedly, my covers list is dominated by male artists, but this is more a consequence of my vocal abilities; I can appreciate music from any artist for the art of the song.
I've always struggled with the idea of whether I should give up the covers altogether and focus on my original music. I have enough original music to fill a few hours, but these covers provide a few things. On one hand, these songs provide a window into my musical experiences. Each cover represents a part of who I am and how I came into music. This alone isn't really enough to convince me to keep playing them, but there's also the audience themselves. Most people have heard most songs that I cover at some point, and that provides the audience with a shared experience, something familiar. It's like building a relationship and finding that rapport.
Then there are traditional songs. Songs that had an author at some point that some folks may remember, but the tunes are now embedded almost as deep as our instinct. Twinkle Twinkle, 3 Blind Mice... There was a time I did a children's fair for a few years where Kalamazoo Psychology hosted an event celebrating National Children's Mental Health Awareness day. For this event, I leaned heavily on the traditional songs while including some select covers and originals. One year, I opened with classical music and transitioned to singing about halfway through my set. It worked well for that audience. In all my gigging throughout the decades, working to understand the audience has consistently helped me choose the right songs for the event.
With all of that, I'm not a jukebox. I know a lot of songs, but I probably don't know the one you're about to ask me to play. There's really nothing more disappointing to a musician than spending multiple hours every day, every day of the week, for decades just to have someone roll their eyes when they don't know a specific request. I can, at any moment, pick up a guitar and harmonica and hammer out over 5 hours of music. There are 10s of millions of songs, and it's just not reasonable to expect anyone to know them all. And here's the deal. I memorize the songs I do. Yes, I can read music, I can read chords, and I can read lyrics. I could stand in front of you and recite a song from a sheet of paper or a tablet... but, I don't. I know there are some gigging musicians that perform this way. I can't. For me, I need to get into the song, understand the message, and it must resonate with me. Then, I'm going to practice a song 1,000 times before I perform it on stage... it's just part of who I am.
Because of my apparent need to have a song resonate with me, I also have picked a few songs that are little more off the beaten path. There have been occasions where I choose a song to cover, practice, get out on stage, give it my all, and no one has ever heard it before. This can be a little off-putting for everyone, without a basis of comparison, most people don't really react to new songs very well... If it's new and it's an original, people are much more forgiving. The expectation seems to be either it's an original or recognizable, if a cover isn't recognizable, it's sometimes better around the campfire.
So, pros: Rapport with recognition, display a reflection of myself. cons: expectation I know every song, confusion of obscurity.