As well, mix up the combination of GCD. Start with a C. Start with a D...etc.etc.
Mix up the tempo, mix up the meter 4/4, 3/4, 6/8....
Many a pro have used three - four chords and made a life long career doing it. Case in point, John Prine - GCD , Gordon Ligthfoot, A,D,E, Neil Young, D,G,A .... and many more.
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