There are 2 repositories under rich-snippets topic.
Collection of structured data snippets in Google preferred JSON-LD format.
WordPress Plugin that Boost CTR. Improve SEO & Rankings. Supports most of the content type. Works perfectly with Google, Bing, Yahoo & Facebook.
Classic SEO is the first SEO plugin built specifically to work with ClassicPress. A fork of Rank Math, the plugin contains many essential SEO tools to help optimize your website.
SchemOrger is a Java Library for generating schema.org hidden html snippets for SEO and Rich Snippets. It will generate hidden schema.org metatags for your page.
MediaWiki extension to generate Google Rich Cards metadata for article pages
SCHEMA for Article is simply the easiest solution to add valid schema.org as a JSON script in the head of blog posts or posts. The provided LD-JSON is validated from the google structured data.
Reviews.co.uk Magento 2 Integration
Module for Prestashop 1.7 - add structured data in JSON-LD format for your store. Adds LocalBusiness, Website, Webpage data.
HTML example pages search engines and social media
Yasr – Yet Another Stars Rating WordPress Plugin.
WordPress plugin for custom JSON-ld schema markup within WordPress posts & pages.
JSON Structuring Markup is simply the easiest solution to add valid schema.org as a JSON script in the head of posts and pages. The provided LD-JSON is validated from the google structured data.