WP Rocket - WP Rocket offers a caching plugin for Wordpress.
Kingshiper Image Compressor - With Kingshiper Image Compressor, you can easily compress, optimize and reduce jpg, jpeg, png, svg and gif file to a smaller size in seconds.
Yoast - Yoast offers plugins to improve SEO and optimize web sites and blogs.
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
Wordfence - Comprehensive security plugin for WordPress.
Image Compressor - Windows/Steam desktop tool to compress images and save size with almost the same quality.