The Scepter of the Crimson Spirit

To activate the scepter, cast a healing spell into it (cure wounds or healing word). While activated, either make an attack with the scepter (as a mace) or cast a damaging single-target spell. This causes the spirit within the scepter to focus on that target. Your spells and melee attacks with the scepter against that target thereafter deal +1d6 slashing damage to that foe. When that foe would otherwise fall unconscious, the spirit temporarily leaves the scepter to deliver a coup de grace to the target (in a very messy fashion). The spirit then uses some of the slain character's essence to heal the wielder and/or the wielder's allies. The total amount of healing is 1d8 per 2 HD of the target, to a maximum of 5d8. The spirit prioritizes healing targets intelligently. Once the crimson spirit has killed something and delivered healing, the scepter cannot be activated again until the wielder completes a long rest.

Lanth's Ancient Sentinel Armor 

Bone Mask of the Naga

Very rare, requires attunement

This mask is made from the skull of a bone naga, and grants the wearer some of its traits when the mask is attuned.

• Darkvision, 60 ft
• Resistance against poison
• Each time you encounter another bone naga, you may choose one of the following:
• Ignore the bone naga's damage immunity to poison
• Become invisible to the bone naga until you take an action that would normally break invisibility
• Ignore the bone naga's condition immunity to charmed
• Deal 2d8 extra damage the first time you deal damage to the naga 

Vardevain's Rod

Unique, attunement possible

Vardevain's Rod is made of a dark metal, with a twisted cage on one end that holds a mote of sickly green light. While unattuned, the rod allows its wielder to add 1d8 damage to any spell that deals necrotic or cold damage, once per long rest.

Attunement requires the binding of an incorporeal undead to the rod, to act as a conduit of power. Once it is attuned, it has the following properties:

• +1 bonus to spell attack rolls, spell DC rolls, and cantrip damage rolls.
• Instead of adding 1d8 to the damage of a spell once per long rest, it has 8 charges. Each charge adds 1d8 damage to a spell that deals necrotic or cold damage. The rod regains 1d4 charges every day at midnight.
• It grants advantage on any Arcana checks to perform necromatic rites (if needed).
• It possesses a fragment of Vardevain's intellect. 

Blade of the Deep Waters

Rare, requires attunement

This short sword bears a wave-like pattern in its metal, indicating both a connection to elemental water, and extraordinary talent in its forging. When attuned, it bears the following properties.

• +1 bonus to attack, damage, and saving throw DCs triggered by weapon attacks
• The weapon changes its properties whenever it is used to defeat an amphibious creature, an elemental connected to water, or a creature native to the sea. It does not change if you defeat a second creature of the same category as it already reflects. If a creature could reasonably belong to one or more of those types, determine the effect randomly at the time the creature is defeated.
• Amphibious: While carried on your person, the weapon increases the time you can hold your breath underwater tenfold. If carried by a creature that cannot breathe air naturally, the creature can hold its breath in air ten times as long.
• Elemental Water creature: You can enter a hostile creature's space and remain there. You can move through a space as narrow as 1 inch without squeezing.
• Sea native: Once per short rest or long rest, you gain a hunter shark's blood frenzy ability, gaining advantage on melee attack rolls against any creature that doesn't have all its hit points.  

Horn of the Long Night

Rare, may only be used by one who has made a pact with a Highlord of the Fey

While attuned to this horn, any time an undead would be charmed or frightened by an effect you cause but is immune, it is harried instead, by phantasmal hounds of the Wild Hunt. Harried is a condition that causes the following:

• The creature must pass a Wisdom save against the original spell DC to leave its current space. On a failure it may still move, but if it chooses to do so, it takes 1d6 damage (scaling up with level as per a cantrip - 5th, 2d6, 11th, 3d6, 17th 4d6). Once the creature passes the saving throw or takes damage, the harried condition ends. 
• The creature suffers disadvantage on all Concentration, Intelligence, and Wisdom checks (not saving throws in general, though).

The Vial of the Black Moon

Uncommon, requires attunement

While attuned to this vial, you gain resistance to radiant damage. Once per short rest, you may open the vial as an object action. This ends your resistance to radiant damage until you take a short rest. Add one of the following to the next successful weapon or spell attack you make before the end of your next turn:

• The target must succeed a DC 13 Wisdom saving throw or be frightened until the end of its next turn.
• The target takes an additional 1d8 necrotic damage from the attack.
• The target loses resistance (but not immunity) to radiant damage until the end of your next turn.
• The target loses resistance (but not immunity) to necrotic damage until the end of your next turn. 

Necklace of Sioctana's Solace

When a creature other than you currently affected by your protection from evil and good, sanctuary, shield of faith, or warding bond spell takes damage from an enemy’s attack or spell, you may cast any cantrip you know as a reaction. This power recharges in 1 hour.

Sorilka's Cleaving Blade

Any slashing weapon, very rare (requires attunement)

You gain a +1 bonus to attack and damage rolls made with this silver and magic weapon. Any creature with damage resistance that is specifically overcome by a silver weapon, or otherwise has a weakness to silver weapons, suffers an additional 2d6 slashing damage from attacks made with this weapon.

First secret: The first part of Sorilka's name is Tuorthienna. Learning this grants the weapon the following additional property: as a reaction when you would take necrotic damage, you reduce the necrotic damage you suffer by your weapon damage value, including your ability modifier and the weapon's bonus to attack and damage rolls. 

Story: Now Sorilka is one of the best fey knights serving Rathmorvan, the Silver Knight, He Who Cleaves in Silver. From time to time, she grants her blade to a mortal that she believes will serve the Silver Knight’s purposes, whether through intentional service or simply the path of whatever they were doing of their own will. In this way it came to Gamble.

At the time she gave him the blade, she caused its silver to shift into a form more suited to its new bearer; it transformed from a greatsword to a halberd, with insignias and engravings representing its new bearer.

Ramoch's Lament

Rapier, very rare (requires attunement)

You gain a +1 bonus to attack and damage rolls with this silver and magic weapon. You gain 1 Combat Superiority die, which is a d6 if you don't have any other Combat Superiority dice. You can choose to maximize the result of a Combat Superiority die after you see the die result. You can do so three times, and regain all expended uses at dawn. The sword holds the ghost of Ramoch, who can sometimes be induced to speak to the wielder.