A simple, but very effective, way to musically expand a single chord is to play a Moving Bass Line under the Stationary Harmony…
C Major Triad with a bass line that walks down the top four notes in a descending C Major Scale…

C Minor Triad with a bass line that walks down the top four notes in a descending C Minor Scale (a la “Hit the Road Jack” and “Stray Cat Strut”)…
