While Stockpile leader ability is restricted only to non-Neutral units, the cards like Siege Masters, Rivian Pikeman or Winch could be used also on Neutrals.

The strongest Cooldown effect amongst neutral units is Colossal Ifrit. An extra trigger of order ability can be worth up to 15 points in Northern Realms deck running full constructs package.

I thought that showcased list is meme tier, but actually went unbeaten on stream. Constructs package is in general overcosted, so the deck is very tight in provision. Consequently I couldn't fit in a tutor for Mutagenerator and you need a smile of luck to find it from red coin. Muta is used to boost Rivian Pikemen and unfound Siege Masters for R3.

Shieldwall leader ability choice is of course all about protecting Colossal Ifrit. Another downside of tight provisions is lack of bait for opponent's hard removal; if opponent is aware, they would always keep the big gun for Colossal Ifrit.

Have fun!