New strongly coupled dark sectors provide elegant solutions to
several open problems of the Standard Model, such as the nature of Dark
Matter and the Strong CP Problem. In this talk, I will explore two
specific realizations. First, I will discuss a solution to the axion
quality problem, in which gauge invariance provides an accidental
Peccei-Quinn symmetry protected by UV-breaking sources. Then, I will
examine a model of dark pion Dark Matter, showing that the inclusion of
a dark topological theta term in the Lagrangian induces new resonant
processes, which allows reproducing the correct Dark Matter relic
abundance and address the small-scale problems of the Lambda-CDM model.