Imagify - Optimize and resize images online and through your CMS.
WP Rocket - WP Rocket offers a caching plugin for Wordpress.
Cloudinary - Cloudinary is a cloud-based service for hosting videos and images designed specifically with the needs of web and mobile developers in mind.
Autoptimize - Autoptimize makes optimizing your site really easy.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
WP Super Cache - A very fast caching system for WordPress that produces static HTML files.