Axion-like fields are ubiquitous in high-energy physics. Their symmetry properties also make them favored ingredients in many cosmological scenarios ranging from inflation to dark matter. The resonant, nonperturbative decay of these axion-like fields into both standard model and dark photons is a generic feature of these models. In this talk, I discuss the phenomenology of resonant axion decay into gauge fields. In particular, these scenarios can result in a significant stochastic background of gravitational waves. In the cases where the dark photons are massive, the resulting vector abundance can constitute the dark matter in the Universe today. When the dark photons are ultra light, these models provide a realization of fuzzy dark matter. I also discuss the weak-field, non-relativistic limit of these theories where the vector nature of the fields leads to novel soliton solutions that differ from those in the corresponding scalar case.