I use 2 decks so I can quick switch for bosses and mobs.
For my mobs I have and blades, traps, auras, etc.
For my boss I keep some but mostly judgment and chimera (and blades, traps, auras, etc) But it is smart to put good tc (Astral spells, heals, and other useful things.) Also make sure you have heals just in case. Another great spell is feint. get those in whatever form you can and your good.
and blades, traps, auras, etc.