This chapter aims to identify visualizations of similarity in the top-cited published literature on the technology evolution of PA-WECs and to highlight potential research gaps and future research directions using the keywords-clustering-driven knowledge-structuring model. The results of this chapter revealed: (i) the characterization of the patterns, including contributive forces with a high influence factor in the PA-WEC domain; (ii) the relevance of the technological enhancement of the PA-WEC systems, and (iii) the application of the KCDKS model in characterizing the wave energy technologies. From the bibliometric study, cutting-edge frontier topics were identified that future researchers may consider in their PA-WEC research. It was found that ecological risk assessment, wave-to-wire models, control systems, nonlinear hydrodynamics, artificial intelligence, multi-frequency resonance, and wave farms are the leading domains needing promising solutions to enhance PA-WEC technologies. Lastly, the critical challenges in PA-WECs and the potential future research directions were summarized.