Depends on the troops you want to use.
Depends on how the troops will be updated in the next patch.
Depends on wether you want to blindly follow the decks higher leveled player came up with or if you want to come up with something you created.
Depends if we are talking of an offensive deck or a defensive deck.
But if I was to list cards that I’d unlock traits on because it boosts nicely the card, making it viable or renforcing it’s viability in various decks, I would list :
~ Common cards ~
- Centaur Scout (2nd and 3rd traits)
- Glade Warden (2nd and 3rd traits)
- Golem (1st and 2nd traits)
~ Rare cards ~
- Alchemist (2nd trait)
- Soothsayer (1st and 3rd traits)
- Star Gazer (3rd trait)
- Templar (2nd and 3rd traits)
- Valkyrie (2nd and 3rd traits)
~ Ultra rare cards ~
- Goblin Rocket (1st trait)
- Gorgon (2nd and 3rd traits)
- Herdmaster (2nd and 3rd traits)
- Knight Coronet (All 3 traits)
- Treant (2nd and 3rd traits)
- Watcher (3rd trait)
~ Epic cards ~
- Atlanta (2nd and 3rd traits)
- Avina (2nd and 3rd traits)
- Green Slime (1st trait)
- Ice Witch (1st and 3rd traits)
- Ragnagord (3rd trait)
- Terraxis (2nd and 3rd traits)
~ Legendary cards ~
- Abhorath (1st and 3rd traits)
- Bone Dragon (3rd trait)
- Celestasia (3rd trait)
- Gloom Lead (2nd and 3rd traits)
- Hydra (3rd trait)
- Kerberos (3rd trait)
- Orion (3rd trait)
Then again, some cards have traits that works well in specific combos, these are just cards I find interesting or that are made more interesting with their traits.
Globally, the traits that I have interest in are :
- Stoneskin / Armored
- True shot
- Elemental Links
- Elemental Spirit
- Huge / Big
These are all traits I have searched in the troop menu to find all troops having these.
Now this is not a list of all troops I have unlocked traits on first. I miss a lot of them. These are only some troops I find interesting and would like to have these traits unlocked on.
But as I made a couple teams working nicely for me and don’t feel the need to unlock more for battle purposes, I only unlock traits to improve my kingdoms power level, thus improving my resources and so my ability to be able to adapt myself to whatever my comes in future development of the game.