Love Nova Launcher! It offers so many customisation options, particularly in terms of home screen and app drawer layout, icons and fonts.
I remember a few years back when my phone was stolen (I accidentally left it in the back of an Uber) and I was forced to buy a new one. The relief I felt when I started up the new phone, signed into Google and straightaway saw my familiar home screen, courtesy of Nova Launcher.
I guess I was surprised so much was still there given I didn't do a formal backup / transfer between old and new phones, but that's the beauty of the cloud! :)
Edit: Also @distantlight, agree with Cube ACR - I have been immensely grateful having an easy way to record calls. It has a button to allow you to start and stop recording in the middle of a call so for me, it was piece of mind, especially during legal scrapes! But as another commenter has said, I feel like it stopped working at some point so no longer have it installed..