Players connect in communities inside or around games and form friendships that can be translated into other games or even in the real world. Players' social networks are a precious source of information to understand how people connect and interact in virtual worlds. Unlike traditional social networks, which are highly tied to everyday life, games' communities have most of their actions online, hence trackable. As a result, those controlled environments can help shed light on complex social dynamics. Social connections shape our behaviours because of peer pressure and social contagion. This phenomenon is amplified in online networks by particularly influential individuals: influencers. Although this concept originated in social media, recent research shows how influencers can also exist in games and can impact players' long-term retention. But who are games' influencers, and how can we find them?