What troop type goes against naga troop tour best?
Garuda has the trait “Naga Slayer,” as does Prince Azquila and Raven. All three will do double damage against naga troops 
here, fixed the missing word
Ah, thank you!
I suppose it did slip my mind that, unless I’m mistaken, no trait in the game makes spell damage against a certain type of creature do more. I think that only happens if spells explicitly state in their description (like “if the enemy is undead, deal double damage” sort of a thing. Not sure if there’s a spell like that for naga — maybe I’ll go check…)
EDIT: None that I found.
Double/triple damage effects are more typical against colors/statuses a troop has, or is belonging to a niche troop like bunninog that does double damage vs. knights a la Monty Python.