I don't believe there is "extra-Biblical" revelation. The canon of Scripture is closed.
However............
I DO believe in illumination, where the Spirit reminds us of what God's Word already says. In many cases, He opens our eyes in a sense to different passages of Scripture so that we understand them in ways we perhaps haven't before. But again, the Spirit, being God, will always show us what those passages mean as God intended them. He will NEVER tell us something that God has not already spoken.
We should always approach Scripture using exegesis, not eisegesis.