'a plethora of people' is a correct and usable English phrase. It usually refers to a large number or variety of people or things. You can use it when you wish to emphasize a significant number or variety of people or things. For example: "The foyer was filled with a plethora of people, all eager to see the show.".
Today, interestingly, that power has been discovered by a plethora of people who have little to do with literature.
Photograph: Cleo Fraser/AAP 1.10am BST For now, Abbott has to deal with the current Senate, but from July he and his Coalition government will need support from a number of micro party senators who Greens leader Christine Milne has labeled "a plethora of people who have no idea what their policy is".
"We have psychologists, psychiatrists, a plethora of people who provide care," she continued.
It was a plethora of people dancing, people in their zone.
and a plethora of creative people found their way to the valley, particularly Hebden Bridge.
I have met a plethora of friendly people here -- some, like me, are young, gay men.
The old adage that if you are not filling a certain need in your spouse, rest assure there are a plethora of other people willing too.
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu