In general, there are several free and paid WordPress Schema Plugins as well as endless Themes available to help boost your website CTR and Ranking. But, how well you get to see the results of any Schema Plugin depends on various implementation aspects.
There are special marketplaces where both WordPress Templates and Plugins are available. I recommend making your choice based on the most popular trading platform like ThemeForest.net. In addition to quality assurance (moderation before addition), the platform has such useful functions that simplify the selection process.
The schema plugin involves a collaborative, community activity with a mission to create, maintain and promote schemas. For structured data on the Internet, on web pages, in email messages, and beyond. Schema.org vocabulary uses many different encodings, including RDFa, Microdata, and JSON-LD.