Author here. The annoying thing awsmap fixes: every other inventory tool re-hits the AWS API every time you ask it something. awsmap scans once into a local SQLite file, then you query that offline in plain SQL, or plain English.
pip install awsmap
awsmap scan
awsmap ask which EC2 instances have no Owner tag
150+ services, all regions, MIT. Happy to answer anything, and curious which services you'd want covered better.