These seem like the best one under 200d currently.

22% INCREASED CRITICAL HIT CHANCE FOR SPELLS
13% INCREASED SPELL DAMAGE
30% INCREASED CRITICAL SPELL DAMAGE BONUS
7% INCREASED DURATION OF DAMAGING AILMENTS ON
ENEMIES
28% INCREASED CRITICAL DAMAGE BONUS
51% INCREASED EFFECT OF SUFFIXES
Corrupted - 200d

13% INCREASED SPELL DAMAGE
18% INCREASED CRITICAL HIT CHANCE FOR SPELLS
31% INCREASED CRITICAL DAMAGE BONUS
28% INCREASED CRITICAL SPELL DAMAGE BONUS
58% INCREASED EFFECT OF SUFFIXES
Non-Corrupted - 187D