I don't think there are any tapes... but I think Trump is playing with the media to get them worked up to think there are tapes. It all comes down to what Comey says that Trump said, and what Trump said he said. The media is very excited about Comey's MFRs, but all they are is his written perception of what was said, no matter how many quotes. And Trump has said he will testify under oath, because he and his lawyers know that at the end of the day, it is still his word against Comey.
I go back to the situation - Trump has just fired a guy that he likes. He feels bad about it and says to Comey that he hopes he can find a way to let is go regarding Flynn. I think what Trump meant is that he didn't want to see Flynn go to jail or be publicly crusified for his error in judgement. And according to Comey, Trump never mentioned it again. Now, do you see anything in Trump's character and communications that would lead you to conclude that if Trump wanted the investigation squashed, he wouldn't just come right out and say it? He would have said "I don't want Flynn to go to jail".
Let's not forget that Comey is a Washington player and Trump is not.