Physics reach of $D_{(s)}\to \pi (K)\mathrm{\ell }\mathrm{\ell }$ and other charming null test opportunities

We discuss possibilities to test physics beyond the Standard Model in $\mathrm{\mid }\mathrm{\Delta }c\mathrm{\mid }=\mathrm{\mid }\mathrm{\Delta }u\mathrm{\mid }=1$ semileptonic, hadronic and missing energy decay modes. Clean null test observables such as angular observables, CP-asymmetries and lepton universality tests are presented and model-independent correlations as well as details within flavorful, anomaly-free $Z^{\mathrm{\prime }}$ models are worked out.