Easy, any app that is making less than a million a year, or any app where people have been subscribed for over a year. They pay 15%. Also you didn't specify the app even had to be paid, so any free app counts too.
Unless you actually believe that Tim Cook committed perjury.
One. He knows there are no way to prove him wrong. Just like many other things he had said during Apple vs Qualcomm and Apple vs IMG. When there are ample of evidence his word are either lying by omission or a spin on a word's definition.
Two, AFAIK, he didn't said "they had been doing the change to 15% for under $1M before the actual Epic Games lawsuit was filed, and that it had been in the works for over a year."
He said and I quote "probably has its origins several years ago". They could trace that back as Phil Schiller's letter to Tim Cook on App Store if it needs to be.