Metrics are not populated while creating the reports. when you check the metric data on the sys_metric table, you will find the metrics are not being populated for the table which has no label. 

Steps to reproduce:

 1. In the filter navigator type CMDB reports
 2. Click on create a report
 3. Choose Metric Base as Source Type
 4. Choose any table in the table field.
 5. Click Next two times and try to select a Metric in the "Configure" part of the report Wizard and observe you don't see any metrics available(screenshot below). 

The issue will happen because metric has been disabled for cmdb table which will affect all the child tables.

Check the system glide property glide.metrics.blacklist_tables value if it is set to CMDB. The property will blacklist the metrics for all the child tables of CMDB. That is the reason will be no metrics available on any CMDB child tables.

The table with the largest number of metrics is cmdb_ci_win_server with 4,675 so it may be worthwhile just changing the blacklist property to cmdb_ci_win_server to avoid performance issues with this table as long as you don't need to do reporting on these metrics.