According to a study by Stilian Morrison and Gary Smith, PhD, the top twelve “positive” initials are ACE, CEO, FLY, FOX, GEM, HIP, ICE, JOY, VIP, WIN, WIT and WOW.
I agree with some, but not all. (To me, HIP and FLY are a body part and an insect.) My top twelve monograms would be more like ART, FOX, GEM, IVY, JOY, SKY, SUN, TEA, VIP, WIN, WIT and WOW.
Source: Monogrammic Determinism? (pdf)