Customizr is one of the best responsive WordPress themes. It provides the look and user experience of a smartphone app on any mobile website.
To help increase the loading speed, it comes with a default lazy loading feature. Additionally, the theme features a grid layout and a built-in full-width slider with a parallax effect which results in a stylish design.
If you want to create an online shop, Customizr is WooCommerce-ready, and it has great design options that can be utilized to showcase products.