It's not logically possible to have unrelated Multi-Record Tables shown on one Report, so SAM will show you a warning/alert in the Report Builder when this occurs. (To help understand why, just imagine trying to merge together a spreadsheet of all Family's Communications with a spreadsheet of all Family's Documents, where there are multiple rows/records for each Family. It just won't work or look right.)
It is possible to have multiple related Multi-Record Tables in one Report, like if you have a "Background Checks" Multi-Record Table under the "Persons in Home" Multi-Record Table, since one table is directly under the other.
You can actually go many levels down, like Family > Case (multi) > Adoption (multi) > Child > Post-Adoption Reports (multi).
For tables, like Home Studies and Licenses, where you really only want to see the data from the latest record, you can use the Current/Latest Record Functionality for Multi-Record Tables to setup a copy of the Multi-Record Table that only shows the current/latest record, so it can be included on reports with other Multi-Record Tables. "