With the overall theme giving players the opportunity to slot any legendary power they want into any of the three slots in Kanai's Cube - which should lead to interesting build combinations. Although no start date has been set for Diablo III Season 20, dubbed the Season of the Forbidden Archives, PTR Patch 2.6.8 highlights what's coming. Including three new Class Sets.

One each for the Barbarian, Witch Doctor, and Wizard - detailed as follows with information on new/updated items coming too:

Barbarian

New Class Set: Horde of the Ninety Savages

• 2-Piece Bonus: Double the effectiveness of all Shouts. Feared Enemies take double damage.
  
• 4-Piece Bonus: Each stack of Frenzy reduces damage taken by 5%.
  
• 6-Piece Bonus: Frenzy deals 1000% increased damage per stack.

Undisputed Champion (Legendary Item)

Frenzy gains the effect of every rune and deals 300-400% increased damage.

Bastion's Revered (Legendary Item)

Frenzy now stacks up to 10 times and hits an additional time per attack. Each additional hit will chain to any enemies within 15 yards and the damage is split between all affected enemies.

Witch Doctor

New Class Set: Mundunugu's Regalia

• 2-Piece Bonus: Big Bad Voodoo now follows you and lasts twice as long.
  
• 4-Piece Bonus: Gain 50% damage reduction for 30 seconds when you enter the Spirit Realm.
  
• 6-Piece Bonus: Spirit Barrage deals increased damage equal to 50 times your Mana Regeneration per Second.

The Barber (Legendary Item)

Instead of dealing direct damage, your Spirit Barrage now accumulates on the target. When you stop casting, it explodes dealing 400-500% of the accumulated damage to all enemies within 15 yards.

Gazing Demise (Legendary Item)

Spirit Barrage gains the Phantasm rune. Each active Phantasm lasts twice as long, increases the damage of Spirit Barrage by 100-150%, and also increases the attack rate from Manitou spectres.
Now always rolls with Critical Hit Chance instead of Life Per Second.

Wizard

New Class Set: The Typhon's Veil

• 2-Piece Bonus: Double the duration of Hydras and increase the number of heads on multi-headed Hydras by two.
  
• 4-Piece Bonus: Damage taken is reduced by 8% for each Hydra head alive as long as there is one available. Each time you take damage, a Hydra heads dies.
  
• 6-Piece Bonus: Hydras deal 1000% increased damage for each Hydra head alive.

Serpent's Sparker (Legendary Item)

You may have one extra Hydra active at a time and they deal 450-600% increased damage.

The Magistrate (Legendary Item)

Your Hydras now periodically casts Frost Nova and deal 450-600% increased damage.

Etched Sigil (Legendary Item)

The bonus granted by this item now occurs 1 second after channeling has begun.

Deathwish (Legendary Item)

The bonus granted by this item now occurs 1 second after channeling has begun.

As a Barb player and sometimes Wizard these new sets definitely sound interesting, especially with Frenzy not being all that great for quite sometime. And Hydras should be a breath of fresh air after the domination of Archon builds. Sadly, this does mean no new Demon Hunter set until Season 21.

The PTR for Season 20 is set to go live on February 6 - and for the full patch notes, head here. And for more insight into the design methodology behind Diablo III, the current seasonal approach, and the new sets, be sure to check out this deep dive from the team.