There are many synonyms for the phrase "plethora of evidence." Some of these synonyms include "abundance of proof," "a wealth of evidence," "an overabundance of information," and "an excess of data." Other synonyms for "plethora of evidence" might include phrases like "a surplus of facts," "an embarrassment of riches," or "an inundation of proof." Regardless of which synonym is used, the meaning remains the same - there is an overwhelming amount of evidence to support a particular claim or hypothesis. By emphasizing the sheer volume of evidence available, these synonyms highlight the strength and reliability of the argument or idea being supported.