Magic Items

The wide blade of this exquisite weapon is inlaid with draconic runes of violet amethyst. Its grip is fashioned in the shape of a coiled snake, with the pommel as its head. The sword was initially created by yuan-ti smiths on the plane of Vudra. As a mundane blade, it was then lost by its wielder during a failed conquest of a dragon-ruled realm.
It gained its magic over centuries of languishing in an amethyst dragon’s hoard, before being recovered by a raid of conquering mariliths. The mariliths returned it to their home plane of Vudra, where it was often used as the first blade of its greatest champions, including — legends say — Shaktari herself.

You gain one 9th-level spell slot, provided that you already have one.

Weapon (longbow), very rare (requires attunement)
When you nock an arrow on this bow, it whispers in Elvish, "Swift defeat to my enemies." When you use this weapon to make a ranged attack, you can, as a command phrase, say, "Swift death to you who have wronged me." The target of your attack becomes your sworn enemy until it dies or until dawn seven days later. You can have only one such sworn enemy at a time. When your sworn enemy dies, you can choose a new one after the next dawn.
When you make a ranged attack roll with this weapon against your sworn enemy, you have advantage on the roll. In addition, your target gains no benefit from cover, other than total cover, and you suffer no disadvantage due to long range. If the attack hits, your sworn enemy takes an extra 3d6 piercing damage.
While your sworn enemy lives, you have disadvantage on attack rolls with all other weapons.

This elven bow has the soul of a Thayan rebel permanently

You have truesight out to a range of 60 feet. This blessing is found in the Dungeon Masters Guide.

The hilt of this weapon is covered with carved, ancient Rellanic runes that seem to comprise nonsensical words or, possibly, a list of proper names.

Weapon (warhammer), legendary (requires attunement)
Matalotok, the Frost Father, is an ancient hammer fashioned by Thrym, the god of frost giants. The favored weapon of the demon lord Kostchtchie, Matalotok is frigid to the touch and wreathed in mist.
You are immune to cold damage while holding Matalotok. Whenever it deals damage to a creature, the hammer radiates a burst of intense cold in a 30-foot-radius sphere. Each creature in that area takes 10 (3d6) cold damage.