That's an odd question. Some of the things that Godly Christians genuinely disagree on ARE matters of heresy -- if consistently followed through. Arminianism is an example. If someone were a CONSISTENT Arminian, I don't know how we would avoid the charge of heresy. But I know MANY Godly 'Arminians', who are happily inconsistent in their Arminianism. The same could be said of the charismata and a host of other such issues.
Within our own fold, I can think of Baptism, the supra/infralapsarian debate, the millennium, approach to apologetics, approach to Genesis 1, church polity, ... and these are just right off the top of my head. There are also literally thousands of smaller debates -- whether Children's church is appropriate is a debate going on right now, for instance.
So I'm not sure what you are looking for. Are you looking for official/historical debates?