My one is Nemus Launcher, you can lock your apps (like contacts, messages, Facebook and whatever you chose) when you give your phone to someone, you can hide apps from the apps menu, and you can make folders in the home screen/apps menu, you can change their color and there are other extras, but the main reason why I like it is because its lightweight and it doesn't eat your battery, there's no PRO version, it's only a free one w/o ads and 'buy-to-use' features.