Testing nonstandard neutrino properties

Neutrinos provide a compelling avenue to explore physics beyond the Standard Model (SM). This proceeding is a brief summary of a plenary talk given at the 12th Neutrino Oscillation Workshop (NOW2024). We present a discussion on various topics on neutrino non-standard properties, such as the origin of neutrino mass, their decay modes, interaction mechanisms, and a potential connection to dark matter. Constraints and observational results from cosmology, astrophysics, and laboratory experiments are reviewed to illustrate the interplay between neutrino physics and broader questions about the universe.