Remotely operated vehicle (ROV)-based inspection, maintenance, and repairs (IMR) services are costly because operations are traditionally executed by a hired subsea contractor, who then hires a specialized vessel with an entire crew from the vessel owner or the shipping company. Even though this is an established method considered relatively reliable in comparison to human divers, there is a growing need for more versatile, efficient, and economical IMR methods. Innovations that require no or less use of support vessels are mitigating this challenge. The current ROV classifications do not adapt to these innovations. Hence, the lack of a widely accepted ROV classification. Thus, this paper reviews ROV classifications and proposes a classification that poses no hindrance to innovation and conforms to modern developments. The paper then illustrates and reviews the emerging methods of conducting IMR operations by putting together in a concise, yet resourceful manner the ROV technologies and their various configurations to provide a basic meaningful understanding to the audience. This paper also provides a summary of the comparison of the methods and some of their challenges.