Abstract: Complex dark sectors are models where a 'sector' of new particles with intra-sector interactions are used to extend the Standard Model. Motivated by theoretical considerations such as the Hierarchy Problem, these models generically also provide dark matter candidates. In this talk I will cover a range of astrophysical probes from the indirect detection of dark matter to using cosmological simulations to study sub-galactic structure, and outline how these methods are sensitive to the novel interactions and signatures that become possible in new dark confining sectors, or models of atomic dark matter. Event recording: