Cross-correlations between zero-moment maps of molecules with significant extended emission and with the continuum (marked with 3 mm). For each molecule, the maximum correlation is marked in boldface. Each molecule in any of the two enclosed frames has their maximum correlation partner in the same group to which they belong. The top-left and bottom-right framed groups correspond to the so-called Shock and Continuum groups, respectively. Below the cross-correlation matrices, we list explicitly the members and the specific transition used. For completeness, we include NH2D despite this molecule not being part of either group. The data used to create this figure are available.