As a continuance of whether we can truly know anything about God's affairs and also whether all Christian views need a Biblical basis, I was curious if there were any instances of God's influence on humanity that are not mentioned in the Bible. On a basic level, many people like to believe that God intervenes from time to time in answering prayers; surely all the ones post-Bible aren't documented in the Bible (like, if you had a prayer answered yesterday, obviously it's not in the Bible). I'm looking for something a bit more substantive than small answered prayers though, like God revealing himself to a group of people or something of that nature, which isn't strictly found in the Bible but most/many/some Christians hold the event to be true in the Christian lore.
What are some of the situations accepted by Christians in which God performed some act, or revealed himself, or otherwise influenced mankind in some way that is not mentioned in the Bible (if any)?