Listing every MTG enchantment The Planeswalker has would be excessive, but
Counterbalance will passively counter every spell tossed, Orbs of Warding/Leyline of Sanctity grants Hexproof to null spells targetting The Planeswalker, activated non-passive counterspells exist (though some can be activated with a tad of Causality via split-second), Lunar Force to counter more spells, Dovescape to turn spells into birds(?), Hive Mind to copy spells The Player casts, Decree of Silence as Lunar Force but better, Summary Dismissal as Counterspell but way better (not passive), counterspells via draining the mana out of it (not passive), so on so forth.
It's an excessively long list.