Generally it is good to keep books by the “opposing sides” to know what those sides teach and believe. Irenaeus and many other early Christians had a firm understanding of non-Catholic heresies. They most likely read the works of these pagans and gnostics. So, keep your library.
If you have some books that are repetitive in content, then see if you can donate to your parish library. Personally I believe that parish libraries should have a shelf that contains works by Protestants, Orthodox, Jews and Jehovah’s Witnesses, since it is valuable to know what the other side teaches to know what you yourself believe. But that’s just my fantasy. A more reaslistic possibility is for you to give those books to your Protestant friends.