Using PkHeX and Powersaves to gen Pokemon won't get you banned, if you use legal and legits Pokemons and items online. Wasn't banned event with all Z crystals, Marshadow, and a lot of mage-stones you can't usually have in-game, but if I use them online, I think they'll get me.
But I don't think we have the exact things they're considering like "cheating" and they ban..