I recommend the Wattson FY-6 Classic Fuzz. I have one of the originals that was labeled "Superfuzz". It looks and sounds exactly like my old bluish-grey Univox. I've tried some other Superfuzz clones and, to me, they didn't make the grade.
capturing the precise tone of the original classic fuzz pedals from shin-ei and univox was our primary goal in designing the wattson classic fuzz fy-6.