if ever there was one

• if ever there were one, if ever there were some
• if there ever was one, if there ever were one
• if I ever saw one, if I've ever seen one

if ever there was one

1. Used to emphasize the truth of a characterization.

   Synonym: if I ever saw one

   He's a plagiarist if ever there was one.

• like no other
• like nobody else

• “if ever there was one”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present.
• “if ever there was one” in Longman Dictionary of Contemporary English, Longman.