Watch the Day 11 online guitar lesson by Ravi from Learn Guitar in 21 Days
With the four chords that you know, the number of songs you can play increases even more. There are certainly a number of songs that use these four chords, but you will find hundreds, probably thousands, that use combinations of two or three of these four chords.
So go ahead and explore the list and your ability to hear the songs in your head. Try ones that you haven't done before, and remember, add some rhythmic strums too. Don't feel that every chord has to have the same rhythm, as I demonstrated in the previous video segment.