Several Standard Model and General Relativity's extensions predict the existence of exotic ultra-light bosons of arbitrary spin. Their coupling to ordinary matter is feeble and therefore are difficult to be tested through direct detection, making them ideal candidates for dark matter. The recent emergence of gravitational-wave astronomy and the growth of high-energy astrophysics observations give the opportunity of testing these exotic bosons through gravitational interactions. In particular, light-mass bosons are expected to trigger the extraction of energy and angular momentum from black holes (superradiance), therefore suggesting the idea of using black holes as particle-physics laboratories and detectors.