Satan was in existence with God before creation so is there more created we don't know about?

While this is true, the Angels had written a book entitled "Satan's Bible" or "The Satanic Bible" while this has been updated in recent years, it displays prominent evidence of satan's actions up until the point of which he had persuaded Adam & Eve to eat from the forbidden tree's fruit. Sentences in his bible make statements in order to justify the reasoning behind his actions, but the written confirmable text to give a picture of what Satan looks like, or how he was created cannot be found. Any text claiming to give a description of how Satan was created or what he looks like has been forged and must be treated as such.

Hope this helps!