If you have a report that you want to keep handy, you can tag it as a "favorite". In a list of saved and built-in reports, right-click on a report and select Mark as "favorite". Next time you see this report on a list, you will see a new section called at the top and this report will be on it.
Recently-used reports take priority over favorite reports: If you've used a report recently it'll show under rather than .
Don't like a report anymore? Right-click on a "favorite" and Un-favorite it.