There are many different 3rd party home launchers available for Android devices which is one of the reasons why many users love the platform, because it opens up customization options. One of the more popular launchers on the Play Store, Action Launcher 3, just received a huge update recently which ushers in a handful of new features, as well as the "to be expected" bug fixes and improvements which will help to make Action Launcher 3 the smoothest it's ever been. Those using Action Launcher 3 on Android 6.0 Marshmallow will also notice a few key changes here and there including the ability to now use Marshmallow's "reveal" app launch animation, and Launcher 3 now uses the Marshmallow permission system. For anyone who really loves customization, icon packs can now be used with the free version of the launcher, something which wasn't capable before.
If customization is crucial to your Android experience and icon packs are part of that whole process for you, the all new quick edit feature is a UI worth checking out. It takes your icon packs and suggests icon alternatives for you to switch out to on the fly, making this a lot faster than opening up the icon pack app dashboard (assuming the icon pack you're currently using offers this features) or without having to go into the Action Launcher 3 settings to apply the pack from there. Quick Edit will only offer suggestions if there are any icon packs installed on your device, though. What users may appreciate is that they can change one icon or a few with Quick Edit, so if you only want to change the icon for the Chrome browser and not the rest, you don't have to apply an entire pack. This also translates to the app drawer icon and not just the icon on the homescreen.
With the smartsize icons, this is essentially the same as what you'd find from icon normalization inside of Nova Launcher. Smartsize takes the icons you have for apps already installed and resizes them automatically to fit the design guidelines of material design, much in the same way that Icon Normalization does. The Icon Picker has also been updated, and Google calendar icons have now been bundled to show the correct date on the icon. For example, since today is the 21st of December, the Google Calendar icon will show this day of the month and so on. The update is already live in the Play Store and if you have the app you should be able to immediately enjoy these new features.