Axions are attractive candidates for theories of large-field inflation that are capable of generating observable primordial gravitational wave backgrounds. These fields enjoy shift symmetries that protect their role as inflatons from being spoiled by coupling to unknown UV physics. This symmetry also restricts the couplings of these axion fields to other matter fields. At lowest order, the only allowed interactions are derivative couplings to gauge fields and fermions. These derivative couplings lead to the biased production of fermion and gauge-boson helicity states during and after inflation. I will describe some recent work on reheating in axion-inflation models that are derivatively coupled to Abelian gauge-fields and fermion axial-currents. The biased production of fermion helicity-states in these theories has interesting phenomenological implications for leptogenesis, while gauge preheating in this class of models can be extremely efficient, and can result in cosmologically relevant magnetic fields.