I began this list looking through all of the warscrolls for models with attacks “X” with X being models in range.
-1 bravery to enemies within 6″
6+ save while within 12″ of hero
Enemy failed battleshock heal 1 wound to a hero within 6″
Half your units can be set up to deepstrike
Unmodified charges of 10+ allow you to attack right away. (And later, in the comabt phase)
Artefacts, Command Traits & Abilities
Your general gets spectral summons command ability. (You’ll use this often if you pick dreadblade as general)
At the start of the movement phase pick a friendly nighthaunt on field, then teleport it to your general. Wholly within 12″ of your general and 9″ from any enemy.
If you instead choose Olynder, she has the ability to return a summon able model to all NH units within 12″. She could actually use spectral summons to return an in jured unit to her, healing it later in the game, recycling which ghasts are used for combat and which are used for shooting.
(General) Dreadblade Harrow: can keep deepstriking. Good combination with Spectral Summons.
-Ruler of the spirit hosts
Olynder: mortal wound output and chainghasts durability if she is general.
Reikenor: easy Cogs cast to change your deepstrike to charges to 7″
3×10 chainrasp horde: battleline tax/higher body count for objectives on your side.
Their close combats have attacks/model in range, which works well vs hordes after they snipe the armor.
Magic, Endless & Realm Spells
Cogs. 7+ cast. Adds 2 to move and charge of everyone. Reikenor has the ability to give himself plus to cast so it makes it a little more consistent to get off a 7″ charge after deepstrike.
New purple sun price on Reikenor is nice.
The plan is to set up chainghasts in reserve and remove armored targets with rend -2 and charge in and take out hordes with their close combat.
With dreadblade Harrow you can bounce them around battlefield in later turns so you can focus heavily on one side or enemy when needed. If you chose Olynder as general you can afford to take some hits more, but you also need to keep in mind chainghasts could get caught in combat doing very little damage against low model count units.
Model them as undead kharadron overlords!