In DS2 there are no reagents that boost your CM/NM level. While there was equipment with these kinds of bonuses in DS1, with the advent of experience sharing and a total revamp of the way that magic works for DS2 these bonuses became totally redundant and were removed from the game.
If you want to power up your spells, virtually every spell uses intelligence as its controlling attribute. Only the curse, embrace, wrath and weapon enchancement spells use level as a controlling attribute, but these also gain more powerful bonuses from the skill trees to balance them out. Sharkull's reagent bonus suggestions are ideal for powering up any magic user
From cradle to coffin... Shall my wickedness... Be your passion