Lynn (usually female, but sometimes male)

This is a nick name also.

Bernie (often a nickname for Bernard (masculine) or Bernadette (feminine)

I have met men with names commonly considered female.

Kelly & Leslie

I had a male teacher in junior high whose first name was Jan. I thought it was totally bizarre until later learning that it is a very common male name in Europe.

Pat is completely ambiguous.

Some really good names tossed out here. My DH has a cousin name Leslie. I wonder how often he had to fight his way in school with bullies. Naturally, he goes by Les.

Here is one we all know from TV. Drew Barrymore and Drew Carrey

Leslie is a last name too. How about Carrie or Carey for a female and Carey Grant ?

Frances or Francis - you have to watch the spelling on those. Tony or Toni.

More nicks - Sam, Micky, Mel, Nicky.