Our primary research question was whether memes and codewords, private or fringe online forums, and hybrid real-world/online militia—the three characteristic tactics that support outbreaks of extremist violence for both Jihadi and Boogaloo extremism—are also prevalent in anti-fascist and anarcho-socialist groups. To analyze the use and prevalence of memes and other coded language and activity, we performed analyses on over ten million social media comments ranging from mainstream platforms (such as Twitter) to fringe online forums on Reddit. Throughout the research, we examined whether the same extremist themes and actions that are characteristic of both Jihadi and Boogaloo extremists—themes such as violent revolution, martyrdom, and having a utopian narrative, and actions such as terror attacks—are also found in extremist groups espousing anti-fascism and anarcho-socialism.