This is slightly different question to the one asked on How do I see how many custom tabs have been created? and I think it could be handy.
I have the same issue as him, I have more custom tabs that my limit. Before I request to hopefully get a limit increase on the number of tabs, I want to get rid of the one that probably are not used.
Someone mentioned that using Using Event Monitoring, could help to check which are the most visited URI, but this Force.com REST API Developer's Guide link doesn't offer much information.
It is also quite confusing the workbench, as it displays a total of 74 tabs, Even more confusing the custom tabs in set up,
that between custom objects, Visualforce tabs and web tabs it shows me a total of 49, and 5 of them doesn't belong to a manage package (as they don't have the white/blue icon).
Has anyone been able to get the list of the most visited tabs? Also, is there a way to clearly see which are the tabs are been count in this limit, because as I mention, either the workbench or the setup menu shows clearly this value.