Just like Highlander Mage, the new Highlander Handlock relies strongly on the power of Zephrys The Great. However, there are several new additions that will make Warlock a bit stronger in this meta.
There is great synergy in combining Zzeraku with Warlock's hero power. Every time you use it or receive damage, Zzeraku summons a 6/6 dragon for free. Such a synergy will allow you to quickly build up the board without using any additional minions.
One of the best new board sweepers is Crazed Netherwing, a dragon that unleashes a powerful AoE similar to the Hellfire spell. In this case, though, you also get a body similar to Duskbreaker.
The last noteworthy card in this list is Abyssal Summoner. Abyssal Summoner conjures a minion with Taunt as big as your hand. For example, if your hand holds 10 cards, then the minion will be a 10/10 creature.