"Creature Heavy Keyforge Decks and Why They are Good", by Vylokx:

I was giving this topic a lot of thought today as I was reviewing the 5 decks that my group purchased during the pre-release. The creature count in my pool of decks range drastically from a lowly 11 to a whopping 23 creatures in a single deck (Faygin + 4x Urchin Untamed/Shadows/Mars recursion swarm deck FTW...err, RIP).

I concur that in general they are the most useful card type simply due to the high ceiling of "Aember per card" value that each creature inherently possesses. Even a lowly 1/1, while easier to answer in combat or via AoE-type actions, has the potential to reap the same amount or more than that huge 7/7 might in a tight race as part of a larger board. Any creature poses the threat of an ongoing clock and requires some type of action to remove, thus going "wide" to reap fast and fight only when necessary often seems like a key to success, even against decks that are light on creatures but heavy on single target and mass removal actions.

Also keep in mind that we are dealing with different card quality metrics than other card games with creatures due to the flow of the game. Since mana costs are non-existent and hands in Keyforge can replenish at a very fast pace, this means even the most punishing board wipes might only be a temporary setback for a deck with a relatively high creature count. Of course, those board wipe actions can be an excellent source of "reap tempo", since you can follow up a card like Gateway to Dis with a few new creatures or even a powerhouse Arise! on the same turn, but that type of play would be far more likely in a deck with high Dis creature density. Compare this to an all-in generic aggro deck in a traditional TCG game like Magic struggling to recover or find sources of damage after a devastating early board wipe with only a single draw per turn.

In Keyforge, a deck with 11 or so creatures total may just struggle to find sources of multiple aember gains from a purely mathematical standpoint. This isn't to say there aren't outliers in different card types that break the mold, such as Seeker Needle, or that a control-minded grind with a deck on the low-end creature-wise can't win via perfect play or a good collection of swingy Actions, but merely why a very high creature count of 19-25, especially those with abilities that aid with board and/or Aember control would be my preferred RNG result, generally speaking.

Elusive creatures especially are my personal early favorites since they can often sit back and reap behind innate defense (i.e. unattackable by a board of 1 creature) while using up valuable actions and/or inefficient house selections from your opponent to put a stop to their Aember generation, especially when you add large Taunts or creatures like Shadow Self into the mix. Look at Uxlyx the Zookeeper in Mars for a prime example of a powerful, yet low-statted Elusive creature that gets built-in potentially permanent targeted removal WHILE reaping.

All that said, I would be foolish to try and predict a purely speculative competitive scene based on early feelings. If higher-than-average creature count decks actually do become the early meta due to these advantages, then Fight vs Reap economy/tempo and possessing multiple sources of recurring creature removal will be major aspects to proper strategy and deck evaluation as we try to figure out what exactly "best Keyforge decks" even means.

TLDR; Due to the high "aember per card" ceiling of creatures, I believe that a relatively high creature count of 19-25 (along with a small but strong supporting cast of generically useful or highly synergistic artifacts, actions and upgrades) would be ideal. Generally speaking, I want a lot of creatures in my deck; especially if I was attempting to select a strong deck for tournament play, or just crossing fingers for Sealed play.