Toxic behavior is known to cause harm in online games. Players regularly experience negative, hateful, or inappropriate behavior. Interventions, such as banning players or chat message filtering, can help combat toxicity but are not widely available or even comprehensively studied regarding their approaches and evaluations. We conducted a systematic literature review that provides insights into the current state of interventions literature, outlining their strengths and shortcomings. We identified 36 interventions and qualitatively analyzed their approaches. We describe the types of toxicity being addressed, the entities through which they act, the methods used by intervention systems, and how they are evaluated. Our results provide guidance for future interventions, outlining a design space based on known systems. Furthermore, our findings highlight gaps in the literature, e.g., a sparsity of empirical evaluations, and underexplored areas in the design space, enabling researchers to explore novel directions for future interventions.