What are some alternatives?
When comparing Yoast Plugins and Jackmail, you can also consider the following products
Gravity Forms - Gravity Forms is one of the best and easiest contact form plugins to create modern forms for websites powered by widely-used WordPress.
WPMU DEV - WPMU offers WordPress Plugins, WordPress Themes, WordPress Multisite and BuddyPress Plugins and Themes.
Wordfence - Comprehensive security plugin for WordPress.
WP Rocket - WP Rocket offers a caching plugin for Wordpress.
The SEO Framework - Easy SEO for beginners, an awesome API for experts. WordPress SEO for everyone.
Pareto Security - Pareto Security is a Wordpress Security plugin