It's in There... Trust Us.

Interesting food for thought here. Most evangelical churches (and quite a few others) will claim to be following the Bible and not any tradition; Sola Scriptura is the Latin for that concept. Here's the beginning of a John MacArthur take on it-

The Reformation principle of sola Scriptura has to do with the sufficiency of Scripture as our supreme authority in all spiritual matters. Sola Scriptura simply means that all truth necessary for our salvation and spiritual life is taught either explicitly or implicitly in Scripture. It is not a claim that all truth of every kind is found in Scripture.

The touchy word here is implicitly. A lot of church doctrine is implicit, since it isn't clearly stated in the Bible text. Early theologians had at over the nature of Jesus; is He a godly human, God in a human-looking shell, or what? "Fully God and fully human" was what they hacked into.

Other doctrine is less settled. Arminians and Calvinists will have at it, both quoting scripture in their arguments. Young-earthers will insist upon a one-day=24 hours definition of day, while old-Earthers will read it as "eras." Baptists will not be big on things like healings, prophecy and tongues while charismatics will insist upon a "full gospel" that includes such stuff, and they both claim to be Bible-based.

Catholics have a Magisterium, a body of settled doctrine beyond raw Scripture, and Protestants have it, too. The latter don't admit it. Their "Bible-only" is really "the Bible as we see it and apply it", which is often open to debate.