The conventional wisdom that magnetism and superconductivity are immiscible has been losing ground for more than 25 years, in favor of the concept of magnetism-mediated superconductivity. Not only are magnetic interactions required for electron pairing in the famous Cu oxides and the Fe pnictides, but they seem to be the key ingredient for high temperature superconductivity. In this talk, I will follow one of the emerging empirical strategies for design and discovery of novel superconductors: at the crossover between itinerant and local moment magnetism, such exotic, high Tc states have been unveiled. I will illustrate with examples some properties of itinerant magnets, and discuss the interplay of crystallographic and physical properties of two FeX compounds (X = pnictide or chalcogen) as design tools for novel, practical superconductors.