  As a contribution to a memorial volume, we provide a comprehensive discussion
of resonant configurations in analogue gravity, focusing on its implementation
in atomic condensates and combining review features with original insights and
calculations. In particular, we analyze the analogues of the Andreev and
Hawking effects using a microscopic description based on the Bogoliubov
approximation. We contemplate several resonant scenarios whose efficiency to
enhance anomalous scattering processes is compared to that of non-resonant
setups. The presence of quantum signatures in analogue configurations, such as
the violation of Cauchy-Schwarz inequalities or entanglement, is analyzed,
observing that resonant configurations highly increase the entanglement signal,
especially for the Andreev effect. We also discuss how these results have
served as inspiration for the rapidly expanding field of quantum information in
high-energy colliders. Finally, we study the physics of black-hole lasers as
further examples of resonant analogue structures, distinguishing three stages
in its time evolution. For short times, we compute the linear and non-linear
spectrum for different models. For intermediate times, we generalize the
current analysis of the BHL-BCL crossover. For long times, we discuss the
emerging concept of spontaneous Floquet state and its potential implications.
