More restrictive version of the question:
Has the Christian God ever revealed Himself to someone who had never heard of Him before? By this I mean someone who never heard about the Bible, who never heard about Jesus, who never saw a picture of Jesus or the cross or anything related to Christianity. In other words, someone who was completely ignorant in every way, shape and form regarding the Christian faith. Has anyone in such a condition had an encounter with the Christian God that led them to convert to Christianity?
Less restrictive version of the question:
If the requirements above are too demanding, answers addressing less restrictive versions of the question are welcome as well. For example, in today's world it's probably very unlikely to find people who have never heard of Christianity, but it would still be interesting to know about cases where someone, who was barely aware of Christianity's existence and never took it seriously, for some reason received a divine revelation of a very specific passage in the Bible that they didn't even know existed, or had an unexpected experience with the Holy Spirit (like Cornelius in Acts 10) even though they didn't even know that the Holy Spirit was a thing, etc. Essentially, any type of experience in which the individual had no prior knowledge about it and the experience itself only makes (the most) sense under a Christian worldview.
Note: I'm looking for extra-biblical examples, of course.