The phrase "the plethora of" is correct and usable in written English.
It is used to refer to a large amount of something. For example, "There was a plethora of books available in the library."
The plethora of molecules du jour was probably inevitable.
The plethora of selfies now speaks of the difference.
It is not just the plethora of Twenty20 games.
There's the plethora of carby options, for one thing: Pancakes!
The plethora of factions makes the process harder, too.
I don't think he could have handled the plethora of large personalities".
Within the plethora of palaver, one moment stands out as particularly significant.
Less mysterious is the plethora of other four-legged creatures that inhabit the wood.
Holik was more philosophical about the plethora of penalties and what Robinson described as cheap shots.
The plethora of new ways to express those thoughts can only enrich this age-old culture.
They don't have the plethora of styles of food that we have over here.
