Shakespeare is always a good place to start, I would look at the choruses in any of his plays they have excellent material for a monologue, also actually parts of songs of solomon could be used as well.
Galinda the Good has a great monologue about popularity in the musical "Wicked. "
There is also a song in the middle of the scene called, "Popular. " This may be just the thing you're looking for!
There are some really great monologue scenes dealing with popularity, celebrity, and pressure put on those that have either of those things, in "The Little Dog Laughed".
