If you have an Android phone from Samsung, LG, Sony, HTC, or another manufacturer and don't like the skin that the manufacturer put over Android, or want to stay as pure as you can to Android as Google intended it, there are ways to make your phone look like it has stock Android - almost.
Here's how to do it:
Get Google Now Launcher, or Nova Launcher
Google Now Launcher is Google’s launcher app, while Nova is also very close to stock Android with more customization as well as a stock Android icon theme you can choose.
Download Google Keyboard
You can download Google Keyboard on the Play Store if it isn't already preinstalled on your phone.
If you want to get the latest version, you can install it from APK Mirror:
http://www.apkmirror.com/apk/google-inc/google-keyboard/google-keyboard-5-0-18-121010836-release/google-keyboard-5-0-18-121010836-arm64-v8a-android-apk-download/
Download Apps from Google
(Some of these may already be preinstalled on your device)
Google Calendar
Google Calculator
Google Clock
Google Keep
Google Photos
Google Play Music, Movies, Books, Games, Newsstand
Google Camera
I will soon update this article with more information in the future.