Atk <= 3 to avoid Vanquish and Downfall. (Hates Suffocate and Extinguish.)
Def >= 4 to avoid Torch, Hailstorm, etc.
Also, Aegis is nice for protection against everything.
Maybe base a deck around it?
Here's the full list of such units in Hooru:
https://eternalwarcry.com/cards?Query=&Factions=justice&Factions=primal&AttackCosts=0&AttackCosts=1&AttackCosts=2&AttackCosts=3&HealthCosts=4&HealthCosts=5&HealthCosts=6&HealthCosts=7&HealthCosts=8&Types=2&DraftPack=