There’s this post from Business Insider titled, 10 Things You Forgot Your Android Phone Could Do. Hopefully, since most of the “things” are mundane, you really didn’t forget, but in case you did, it’s worth a look.
My favorite things are taking screenshots (which I do a lot for this blog), setting up one-touch dialing for several favorite contacts, voice typing, and hauling stuff around on my phone or tablet as a USB device. I don’t use a lot of the other tips, such as monitoring data use (I use Verizon’s app), so they’re not that cool.
A post that probably has a little more information is this one, which gives 20 “essential” Android tips. Note though, their tip 2 involves Flash. If you’re using Android 4.1, this support is gone.
Finally, you might check out my post about suping up your Android device.