In T1, there aren't that many, so you have to treat most of them as 'essential' if you wanted to go ONLY Heretics (which is probably how they'd work best in T1). Bear in mind that they are site-reliant, and thus you will need to make sure that you have the deck space for that (meaning less for the offense). That said, there are some options. For example, you can decide you want to use Magic Charms since Heretics now have access to that, but if you do you run the risk of not being able to protect the captured characters. If you don't use Charms, then The False Prophet is probably not worth the add. Otherwise, every Heretic should probably at least be considered, with only a couple being 'must adds' (like Creeping Deceiver).
