Gartner's peer insights (TM) on software asset management (SAM) software is very helpful and provides a robust listing of SAM software providers along with this handy definition of SAM
What is software asset management (SAM) software?
Software asset management tools automate many of the tasks required to maintain compliance with software licenses and to control software spending. SAM tools facilitate in-depth analysis of software license position by automating software data collection, evaluating software license entitlement, and highlighting opportunities to minimize risks and optimize costs. SAM tools use details about product-use rights, vendor SKUs and contract terms to automatically determine — and optimize — license position against discovered software. SAM tools have rapidly become the tool of choice for managing software entitlement, in lieu of using spreadsheets, due to the rising complexity of software-licensing schemes.
Details @ https://www.gartner.com/reviews/market/software-asset-management-tools