A free program for Android, by Sarim Techs.

Theme for OnePlus 5

This theme application will provide you with hundreds of HD wallpapers, icons, themes, and more to customize your smartphone to one of the most stylish designs. You will also be able to change the color of the background and icons of your phone.

You can also customize the font style, color, and size of the text. Furthermore, you can add more than a dozen fonts for your phone. And if you want to add more themes, you can download them from the Google Play Store.

You can change the icons of the apps you want. You will also be able to customize the colors of the icons and text.