All the preparations in the world can go for naught if you're a martial character living in a magical world, so it certainly helps to have your own personal countermeasures against the powers of magic that can be brought to bear against you.
Weapon (longsword), legendary (requires attunement by a fighter)
This +2 longsword has a rune symbolizing antimagic on its pommel. You gain the ability to cast dispel magic and counterspell three times each. Your effective spellcasting ability for these spells is Constitution. You must complete a long rest to reset the charges of these spells. Additionally, you gain advantage on attack rolls against any creature which can cast spells and advantage on saving throws against spells cast on you.