Non-LTE departure coefficients for late-type stars. For this version, see primarily The solar sulphur abundance in view of large-scale atomic structure calculations and 3D non-LTE models (Amarsi, Li, Grevesse, and Jurewicz, A&A, submitted), and references therein. The methods were first presented in Non-LTE departure coefficients for large spectroscopic surveys (Amarsi et al., A&A, 2020, 642, A62).