Magic Items

Armor (shield), very rare (requires attunement)

While holding this shield, you can speak its command word as a bonus action to cause it to animate. The shield leaps into the air and hovers in your space to protect you as if you were wielding it, leaving your hands free. The shield remains animated for 1 minute, until you use a bonus action to end this effect, or until you are incapacitated or die, at which point the shield falls to the ground or into your hand if you have one free.

Ring, rare (requires attunement)

You have resistance to acid damage while wearing this ring.

Source: Dungeon Master's Guide
Weapon (any sword), uncommon (requires attunement)
You gain a +1 bonus to attack and damage rolls made with this magic weapon.
Curse. This sword is cursed and possessed by a vengeful spirit. Becoming attuned to it extends the curse to you. As long as you remain cursed, you are unwilling to part with the sword, keeping it on your person at all times. While attuned to this weapon, you have disadvantage on attack rolls made with weapons other than this one.
In addition, while the sword is on your person, you must succeed on a DC 15 Wisdom saving throw whenever you take damage in combat. On a failed save, you must attack the creature that damaged you until you drop to 0 hit points or it does, or until you can't reach the creature to make a melee attack against it.
You can break the curse in the usual ways. Alternatively, casting Banishment on the sword forces the vengeful spirit to leave it. The sword then becomes a +1 weapon with no other properties.

This suit of armor is reinforced with adamantine, one of the hardest substances in existence. While you're wearing it, any critical hit against you becomes a normal hit.

Wand, very rare (requires attunement by a spellcaster)

This wand has 7 charges. While holding it, you can use an action to expend 1 of its charges to cast the polymorph spell (save DC 15) from it.

The wand regains 1d6 + 1 expended charges daily at dawn. If you expend the wand’s last charge, roll a d20. On a 1, the wand crumbles into ashes and is destroyed.

Staff, rare (requires attunement by a cleric, druid, or warlock)

This staff has 3 charges and regains 1d3 expended charges daily at dawn.

The staff can be wielded as a magic quarterstaff. On a hit, it deals damage as a normal quarterstaff, and you can expend 1 charge to deal an extra 2d10 necrotic damage to the target. In addition, the target must succeed on a DC 15 Constitution saving throw or have disadvantage for 1 hour on any ability check or saving throw that uses Strength or Constitution.

Wondrous item, very rare

This book contains memory and logic exercises, and its words are charged with magic. If you spend 48 hours over a period of 6 days or fewer studying the book's contents and practicing its guidelines, your Intelligence score increases by 2, as does your maximum for that score. The manual then loses its magic, but regains it in a century.

Beacon Property

Beacon. The bearer can use a bonus action to cause the item to shed bright light in a 10-foot radius and dim light for an additional 10 feet, or to extinguish the light.