Sometimes we come across a chord that lasts for an uncomfortably long period of time.  We seem to feel compelled to get some variation to relieve the sameness.  We don't want to sound monotonous. Here's an alternate way of addressing such an issue.  

You can follow that chord with another chord whose root is a fifth above the original.  Then you can add the raised fifth of this newly created chord. Make this new chord a dominant chord, meaning, include the flat 7th degree.  

OK, now let's put that in plain English. If you are confronted with an Eb chord for an extended period, after two beats, play a Bb 7th(+5).  How did I come up with that?  A fifth above Eb is Bb, so play Bb7 with a raised 5. The fifth of Bb is F, so the raised fifth is F#.

For example, in the tune Where or When (Richard Rogers & Lorenz Hart) in the key of Eb, the first chord, Eb is held for four measures.  By playing Bb 7(+5) after two beats and then returning to Eb, we can create some sense of movement.  

You can harmonize underneath the melody.  When the melody is Bb and the chord is Eb, you can play in ascending order D-Eb, G under the melody.  When the melody shifts to a "C" melody, you can play in ascending order D-Gb-Ab under the melody note of C.  This fills out with chord tones the newly created Bb7 aug.5.