Services Science is prevalent in academia, government, and industry across a range of disciplines. Services Science is evident in the field of Information Technology (IT) through the formalism of IT Service Management (ITSM), the Information Technology Information Library (ITIL), and ISO standard 20000. While there are standards, methods, research outcomes, and defined processes for IT Service Management, there is not a repository of the IT services that are the focus of ITSM. This paper uses definitions and descriptions from ITSM research as an instrument to identify data in the literature that represents IT service topics. The goal of the paper is to rationalize the data and propose an IT services inventory in the framework of ITSM. The IT service inventory is meant to better enable systematic IT services research and industry IT service planning, implementation, and execution.