History Records for Changes in Anything

Wasn't aware of Journal Entry report, so thank you. Unfortunately, I'm looking for an audit specifically for changes made to Routing Rules, Queue Topics, and Topic Groups, don't appear as system updates from what I can see. 

That information can be located in Setup -> System -> Audit Logs. Those reports will contain record of any system modifications that are performed within the Setup area along with user access attempts. That will not reflect changes on records (tasks, projects etc), only configuration changes like "Who added that field to a custom form?" or "Who added a Severity level of 'It done busted?"

If you want a full audit of record-level changes, you want to start with a Journal Entry report.