GEOforge

GEOforge generates JSON-LD schema markup and meta descriptions for the articles it publishes. WordPress strips inline <code><script></code> tags from post bodies (KSES sanitization) and hides underscore-prefixed meta from the REST API by default, so neither can be set by an external publishing tool without a companion plugin.
This plugin solves that by:
<ol>
<li>Registering a <code>_geoforge_jsonld</code> post-meta key, exposed via the REST API for every public REST-enabled post type, that GEOforge writes to when publishing or updating an article.</li>
<li>Printing the stored JSON-LD inside a proper <code><script type="application/ld+json"></code> tag in the page <code><head></code> on any singular view — posts, pages, and custom post types.</li>
<li>Registering the SEO post-meta keys used by Yoast SEO (<code>_yoast_wpseo_metadesc</code>), Rank Math (<code>rank_math_description</code>), and The SEO Framework (<code>_genesis_title</code> / <code>_genesis_description</code>) for REST API write access, so GEOforge can sync SEO titles and meta descriptions on publish. Each registration uses an <code>edit_post</code> auth check and <code>sanitize_text_field</code>-based sanitization capped at 320 characters. Registration is idempotent — if the SEO plugin already exposes the key for REST, our registration is a no-op.</li>
</ol>
No configuration required. Install, activate, and any GEOforge-published article will get its schema markup rendered correctly and its meta description handed to whichever SEO plugin is active.

GEOforge Schema

Renders GEOforge-generated JSON-LD schema in the page head and opens Yoast SEO / Rank Math / The SEO Framework SEO meta for REST writes.

Tim van Iersel

Adds custom field to the post & pages editor for custom JSON-ld schema markup also known as structured data. The plugin also validates if the JSON is formated correctly. <a href="http://coderisk.com/wp/plugin/websitescanner-custom-schema/RIPS-8iSfZmxGFd" rel="nofollow ugc"></a>
Add your own JSON-ld on every page, post and custom post without the <code><script></code> to show your own custom Schema markup.
Works well with the following plugins:
<ul>
<li><a href="https://wordpress.org/plugins/remove-schema/" title="Remove Schema WordPress plugin" rel="ugc">Remove Schema</a></li>
</ul>
Usecases:
With the combination of the WordPress plugin it’s easy to overwrite the schema on a specific page. 
If a plugin like Yoast SEO or other plugin or theme that generates schema you can disable the schema and add your own custom schema to the page.

Websitescanner Custom Schema

Adds custom field to the post & pages editor for custom JSON-ld schema markup also known as structured data.

GEOforge Schema vs Websitescanner Custom Schema