There are thousands of WordPress plugins available, both free and paid, that can add various functionalities to your website. Here am listing popular free plugins
Yoast SEO: This plugin helps optimize your website for search engines and improves your search engine rankings.
Akismet: It helps block spam comments on your website.
WPForms: This plugin allows you to easily create contact forms, survey forms, and other types of forms for your website.
WooCommerce: This plugin allows you to easily create an online store on your WordPress website.
WP Super Cache: This plugin improves website performance by caching pages and posts.
Jetpack: This plugin offers a variety of features such as site stats, security, and performance optimization.
Gravity Forms: This plugin allows you to easily create forms for your website, including contact forms, surveys, and polls.
Advanced Custom Fields: This plugin allows you to easily customize the fields and information displayed on your website.
WP Smush: This plugin optimize images and speeds up website loading time.
WP Optimize: This plugin clean up and optimizes your WordPress database, which can improve website performance.
All the above are few examples of the available WordPress plugins. Use carefully and evaluate each plugin and make sure it is compatible with your website before installing it.