Item: Frostwall

I had this idea that I would make 2 more items in addition to Frostshard and give a set bonus if you're attuned to all 3, which (surprise!) is a mechanic taken from Diablo 3. So here's Frostwall (set item 2 of 3), a huge tower shield that freezes enemies if they fail to deal damage to you.

Item: Flaming Flense

Multiple inspirations for this one. I was really into the idea of the battle master's Sweeping Attack, and thought that it could relate to the Crusader's sweeping flail attacks from Diablo 3. Then I thought about Diablo 3's Butcher and his dragging attack, so decided that a whip would serve the theme more than a flail. Finally, I figured that a magic weapon needed to have more oomph than a regular weapon, hence fire damage. A whip that deals fire damage, sounds familiar...

Yup, the Balrog's whip.

Item: Frostshard

I was inspired to design an item that had a similar feature to vorpal sword's instant kill (with conditions). I tried to balance Frostshard using vorpal sword as a baseline. I figured that if vorpal sword had a 5% chance to instant kill, that I would double the chance for Frostshard and not include the +3 hit/dam rolls. Here's my table from AnyDice:

Frostshard needs two critical hits in a row to instant kill. The second attack must be made before the start of your next turn (hence this sword is best used by fighters with extra attack), but is made with advantage since the target is petrified. To reach the 10.40% chance of instant kill, I set the crit range to 17-20. Also, since vorpal sword ignores slashing resistance, I thought that I would copy that effect by giving Frostshard +1d8 cold damage (which is a longsword's damage dice).

The icing on the cake for Frostshard is its wand-like property. All in all, this sword is probably overpowered, but only playtesting can tell.

Item: Natasha's Doll

Felt like doing another weird one. This item is named after Natasha (Tasha) of the Tasha's Hideous Laughter spell. I thought that I would follow the theme of named spells and make it tied to this item's triggering mechanism. Named spells are spells like Melf's Acid Arrow, Otiluke's Resilient Sphere, or Mordenkainen's Magnificent Mansion.

Item: Kinetic Armor

I wanted an item that made taking damage give good feels. Most of the time you want to avoid taking damage, but at least with this item there's a delayed benefit to it. I specified plate armor because I assume the "tanky" characters would go for it.

Item: Dueling Weapon

I was able to focus on getting some focused time today, so I give you a bonus weapon that focuses on keeping your focus on the target, with effects that encourage that focus.

Item: Monster Slayer's Suit

For all those times you dreaded getting eaten by an ooze or a tarrasque, you can now stick it to them with this armor that probably tastes like activated charcoal!

Item: Infernal Harness

The inspiration for this item came from a theme I was imagining of a post-apocalyptic wasteland and gasoline. Since Descent into Avernus was announced, I thought it especially fitting if this was a devil's belt of fiery destruction. I combined the utility of a few spells: the area-of-effect of create bonfire's flames and grease's slick surface, the automatic damage without saves from cloud of daggers, and the explosive damage from fireball as well as from staff of the magi.

Item: Covetous Cap

Got a weird one for today. I wanted to confer the benefits of the fighter's second wind feature (and a standard potion of healing) without limit, but at a great risk.

Item: Helm of True Strike

Didn’t have time and was away from keyboard this Memorial Day weekend, so I came up with something quick using my phone. I wanted an item that made the true strike spell relevant again (which many agree is underpowered and a waste of a turn), without changing the text of the spell itself. I thought that dealing critical damage should cover for the turn casting true strike, so that if you’re down to one spell slot for a spell attack, you could try to make that last shot count.

Item: Aegis Boots

Another day, another item inspired by Diablo 3. But this time by the game's respawning mechanic. When designing items, I spend 5% of my time on hashing out the general idea and 95% of my time on carefully wording it using WotC's language to try to cover all bases and prevent exploits. I had the most trouble with this part:

"When you leave the Ethereal Plane, you have 1 hit point and 0 temporary hit points, and any spells or effects affecting you also end."

Rules-as-intended, I want characters to come back as a clean slate such that any effect placed on them (i.e. being poisoned, affected by sanctuary, or in barbarian rage) would not carry over. Did I miss anything?

Item: Vile Cloak

Bonus item for today inspired yet again by Diablo 3! Pox Faulds.

"When 3 or more enemies are within 12 yards, you release a vile stench that deals 492% weapon damage as Poison every second for 5 seconds to enemies within 15 yards."

I thought that it would be interesting to reinforce this item's theme by adding flies.

* UPDATE *

Item: Totem of the Thrill

Today, I was again inspired by an item from Diablo 3: the Warzechian Armguards.

"Every time you destroy a wreckable object, you gain a short burst of speed."

I liked the idea of a raging barbarian who is so amped from the rush of fighting that she will even smash objects in her way. Note that the effect of needing to howl gives away your position if any nearby enemies can hear you. But that's the point of a raging barbarian—you barge in head first like a honey badger.

* UPDATE *

Item: Chaos Gauntlet

The Chaos Gauntlet is my interpretation of the Convention of Elements from Diablo 3.

"Gain 179% increased damage to a single element for 4 seconds. This effect rotates through the elements available to your class in the following order: Arcane, Cold, Fire, Holy, Lightning, Physical, Poison."

My goal with the gauntlet was to encourage players to make strategic decisions when preparing their spells each day (hence the exclusion of cantrips), and also to influence their tactical decisions of what type of damage to deal on their turn.

Though the gauntlet can be attuned to by any class, the damage table clearly favors spellcasters. I still wanted martial classes to get utility out of it though, hence the roll 20 giving the choice of damage type to the player (as well as the +2 bonus to attacks). The other benefit of the roll 20 is that it promotes the idea of "rolling well," so that spellcasters with limited damage spells prepared still have a slim chance of choosing their preferred damage type. (Note that I made force damage less likely in order to balance the table. I assumed that it's somewhat acceptable because force damage has the least amount of resistances in the game.)

NPC: Ambrose Tharch

Ambrose Tharch is loosely inspired by Anton Chigurh, the unstoppable villain from No Country For Old Men. I went with locate creature/object because it is the closest D&D equivalent of Anton's beeping transponder, with physical limits.