Magic Items

Weapon (greatsword), legendary (requires attunement by a creature that has psionic ability)
This magic weapon grants a +3 bonus to attack and damage rolls made with it. While you hold the sword, you have advantage on Intelligence, Wisdom, and Charisma saving throws, you are immune to being charmed, and you have resistance to psychic damage. In addition, if you score a critical hit with it against a creature’s astral body, you can cut the silvery cord that tethers the target to its material body, instead of dealing damage.

Wondrous item, legendary (requires attunement by a spellcaster)

While you are holding this gem, you can use it as a spellcasting focus for your spells.

The gem has 3 charges and regains all expended charges daily at dawn. When you cast a spell while holding this gem, you can expend up to 3 charges to ignore the spell's material components with a gold piece cost, up to 500 gp per charge expended.

When you finish a long rest, choose a spell from any class list. The spell you choose must be of a level you can cast. You know the chosen spell and can cast it with your spell slots of the appropriate level until the end of your next long rest.

This particular medallion is made of coral and shaped like a crab. It hangs on a kelp necklace.

Delver: While underground, the bearer of this item always knows the item's depth below the surface and the direction to the nearest staircase, ramp, or other path leading upward.

This suit of Studded Leather armor is black in color and made from the underbelly hide of a great black dragon. Unlike dragon scales, it is soft & pliable, allowing it to be formed into leather armor. The studs of the armor are diamonds drawn from the elemental plane of Earth and are enchanted not to gleam, so the wearer’s Stealth is not affected. Diamonds may not be removed, and neither the armor nor the stones will retain magic or have any value if somehow separated from each other.

Epic boon, unique
You have wrested away part of Szass Tam’s essence. Specifically, this spark of energy was originally wrested from the vile lich himself, and grants one additional 9th level spell slot, provided that you already have one. This item can be found in the Dungeon Master’s Guide under the entry for Boon of High Magic.

Epic boon, unique
You have wrested away part of Szass Tam’s essence. Specifically, this spark of energy allowed the lich’s simulacrum to navigate the planes – and while you aren’t as proficient with this skill, you can retain a small bit of its power. Choose one of the Outer Planes listed in Appendix C of the Player’s Handbook; once choice is permanent once made. You can use your action to cast plane shift on you (targeting yourself only) and travel to the chosen plane, or from that plane back to the Material Plane. This item can be found in the Dungeon Master’s Guide under the entry for Boon of Planar Travel.

Wondrous Item, very rare
This cube is 3 inches across and radiates palpable magical energy. The six sides of the cube are each keyed to a different plane of existence, one of which is the Material Plane. The other sides are linked to planes determined by the GM.
You can use an action to press one side of the cube to cast the gate spell with it, opening a portal to the plane keyed to that side. Alternatively, if you use an action to press one side twice, you can cast the plane shift spell (save DC 17) with the cube and transport the targets to the plane keyed to that side.
The cube has 3 charges. Each use of the cube expends 1 charge. The cube regains 1d3 expended charges daily at dawn. This item can be found on Magic Item Table I in the Dungeon Master’s Guide.
Created by the wizard Hilather, the six sides of this cube are covered in characters from the language of Alzhedo. The six sides are keyed to: the Prime Material, the Elemental Plane of Fire, the Nine Hells, the Far Realm, the Outlands, and Arborea.

An Ioun stone is named after Ioun, a god of knowledge and prophecy revered on some worlds. Many types of Ioun stone exist, each type a distinct combination of shape and color.

When you use an action to toss one of these stones into the air, the stone orbits your head at a distance of 1d3 feet and confers a benefit to you. Thereafter, another creature must use an action to grasp or net the stone to separate it from you, either by making a successful attack roll against AC 24 or a successful DC 24 Dexterity (Acrobatics) check. You can use an action to seize and stow the stone, ending its effect.

A stone has AC 24, 10 hit points, and resistance to all damage. It is considered to be an object that is being worn while it orbits your head.

Mastery. Your proficiency bonus increases by 1 while this pale green prism orbits your head.

Wondrous Item (Symbiont), Very Rare (Requires Attunement)

This opalescent, symbiotic goo comes sealed in a jar and slowly shifts and moves, as if endlessly exploring the jar’s interior. To attune to this item, you must first drink the contents of the jar, unlocking the following properties.

Resistant. While attuned to Kyrzin’s ooze, you have resistance to acid and poison damage, and you’re immune to the poisoned condition.

Amorphous. As an action, you can speak a command word and cause your body to assume the amorphous qualities of an Ooze. For the next minute, you (along with any equipment you’re wearing or carrying) can move through a space as narrow as 1 inch wide without squeezing. Once you use this property, it can’t be used again until the next dawn.

Acid Breath. As an action, you can exhale acid in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 15 Dexterity saving throw, taking 8d8 acid damage on a failed save, or half as much damage on a successful one. Once you use this property, it can’t be used again until the next dawn.

Symbiotic Nature. The ooze can’t be removed from you while you’re attuned to it, and you can’t voluntarily end your attunement to it. If you’re targeted by a spell that ends a curse, your attunement to the ooze ends as it seeps out of you.

If you die while the ooze is inside you, it bursts out and engulfs you, turning your corpse into a black pudding (see the Monster Manual) allied with the Far Realm.

You have a +3 bonus to AC while wearing this armor. Source: DMG.
This plate armor was recovered from the ursine archons that guard the gate to Mount Celestia. It still smells of bear.
Guardian. The item whispers warnings to its bearer, granting a +2 bonus to initiative if the bearer isn't incapacitated.

Wondrous Item, legendary (requires attunement by a wizard)
This thick tome contains pages of thin, hammered copper and has thing covers of slate. It is held shut by a severed elven tongue. Occasionally, the attuned user of this spellbook finds messages that have been scrawled by someone claiming to be Netherese; this ghostly writer refers to itself simply as “the warlock” and frequently opines on the power of the one true god of magic: Mystryl.

While wearing this belt, your Strength score changes to a score granted by the belt (29). If your Strength is already equal to or greater than the belt's score, the item has no effect on you.

Six varieties of this belt exist, corresponding with and having rarity according to the six kinds of true giants. The belt of stone giant strength and the belt of frost giant strength look different, but they have the same effect.

The storm giant quintessent Dessa imbued this belt with her elemental strength. When the belt’s fantastic strength is used lightning dances around the wearer while a warm desert wind blows in the area. This item can be found in the Dungeon Masters Guide

Wondrous item, Legendary (requires attunement) - This cold steel ring is invisible when unworn but becomes visible when slipped onto the wearer’s finger. While wearing this ring, you can turn invisible as an action. Anything you are wearing or carrying – apart from this ring – is invisible with you. You remain invisible until the ring is removed, until you attack or cast a spell, or until you use a bonus action to become visible again. To avoid being spotted while invisible, you must cover the ring with a glove.