While the assembly of intricate crystals is often attributed to an inherent complexity in building block geometry or interaction, soft-matter scientists have found surprisingly complex structures in many very simple systems in both experiment and simulation in recent years. Inspired by the emergence of complexity from several seemingly simple systems, we screened the phase spaces of multiple isotropic pair potentials and found a wealth of structures with varying degrees of complexity and order. The results of our systematic analysis of the assembled crystals can be used to engineer the assembly of desirable and novel structures in future studies.