I wanted to put it in an awe so that it would increase damage. I never use any offensive skills. Would there be another helpful card other than gryphon?
AWE would do jack shit to you, it adds STR, your damage depends on DEX xD. . .
MVP carding.
Gryphon - Universal card for any Sniper, most Snipers go this way, and usually it's my personal favorite. Adds CRIT wich is fundamental for a SQI'd Sniper.
Kiel - Specifically used for Sharpshoot spam [SQI'd], since its the only offensive Sniper skill that got a considerable cooldown. You require 2 Kiels to have an effective spam though.
SK - Not so used, it's specifically made for flee Snipers, useful in PVM maybe if the character is used properly (not letting yourself get mobbed).
BK *could* work but it doesn't really adds that much damage to be very noticeable.
As for any card that isn't MVP, there aren't much options for damage, since most of them are defensive.