There have been a few posts which list and explains the various Sitecore Admin Pages and what they do, such as this post by fellow MVP Nikola Gocev, this post by Bjørn Klinggaard and numerous other posts as well.
I won’t repeat the useful info already in those posts. But did you know there are a few new tools in the admin pages?
Wondering how you missed them? The release notes for Sitecore 8.1 Update-2 states the following:
The main highlights of this update:
– Includes all relevant fixes from Sitecore 7.2 update-6
Like you, most of us probably skipped over that line for our Sitecore 8.1 upgrades, but there was some useful info in those release notes.