  One of the prime goals of the COMPASS experiment at CERN is the study of the
light meson spectrum, with a particular emphasis on the search for exotic
states. The focus of this paper is on signals of the lightest hybrid candidate
$\pi_1(1600)$ with spin-exotic quantum numbers $J^{PC}=1^{-+}$ in several decay
channels such as $\pi^-\pi^+\pi^-$, $\eta^{(\prime)}\pi^-$, $\omega\pi^-\pi^0$,
$\pi^-\pi^+\pi^-\eta$, and $K_S K_S \pi$. In addition, we highlight new results
for the $K^-\pi^+\pi^-$ final state, which indicate a supernumerary state with
respect to the constituent quark model with $J^{P}=0^-$.
