“Lightflow” is an app for Android devices that have multicolour LEDs. I don’t know how it is on devices other than mine, but on my Sony tablet, by default there’s no way to manage which notifications from which apps turn the LED on, or the colours for every notification. Lightflow allows you to do all of the above. You can assign pup-up or LED notifications for a rather long list of supported apps. This is something that I find very very helpful.

Oh, and the support team for this app seems to do a pretty great job too. I requested support for “FreeNote” [about which I wrote here] to be added, and in the next release it was there.