unforgivenhobbies

Multisite search visibility indicator is a lightweight plugin that keeps you informed at a glance whether your site — or any site in your network — is accidentally blocking search engines.
WordPress has a built-in setting under Settings → Reading called “Search Engine Visibility”. When enabled, it adds a <code>noindex</code> directive that tells search engines not to index your site. This is easy to accidentally leave on after development, and notoriously hard to notice.
This plugin adds a persistent indicator to the WordPress toolbar so you never miss it again.
<h4>Features</h4>
<ul>
<li>Toolbar indicator visible to administrators at all times (front-end and back-end)</li>
<li>Color-coded status: green when search engines are allowed, yellow/red when blocked</li>
<li>Multisite ready: shows a per-site breakdown across your entire network</li>
<li>Each site in the dropdown links directly to its Reading Settings for a one-click fix</li>
<li>Bulk management page (Multisite only): allow or discourage search engines across all — or selected — sites in a single action</li>
<li>Zero configuration required — install and it just works</li>
<li>No external dependencies, no tracking, no bloat</li>
</ul>
<h4>Multisite Bulk Management</h4>
On a Multisite installation the plugin adds a Search Engine Visibility page under Network Admin → Settings. From there you can:
<ol>
<li>See every site in the network and its current visibility status</li>
<li>Select individual sites or all sites at once</li>
<li>Apply “Allow search engines” or “Discourage search engines” in one click</li>
</ol>
<h4>Who is this for?</h4>
<ul>
<li>Agencies managing WordPress Multisite networks</li>
<li>Developers who frequently spin up and hand off sites</li>
<li>Site owners who want a quick sanity check without digging through settings</li>
</ul>

Multisite search visibility indicator

Adds a toolbar indicator showing which sites discourage search engines. Supports WordPress Multisite with bulk management.

Marat Nepomnyashy

Overview:
At the time of this writing, the latest version of WordPress, version 4.7, 
 has functionality to discourage search engines from indexing the whole site, 
 but not functionality to discourage search engines from indexing only certain 
 specific pages and posts of the site.
Robots Meta Whiz is a WordPress plugin that allows site administrators to 
 deploy custom meta robots tags to discourage search engines from indexing, 
 following links from, caching, indexing images from, and / or have 
 additional custom restrictions on only for certain specifically-designated 
 pages and posts.
It is an easy way to discourage search engines from indexing only specific 
 pages / posts.
This only applies to search engine robots, and will not effect the site’s 
 local search functionality.
Technical summary:
Plugin works by hooking-in special logic into the action ‘wp_head’ to inject 
 the tag <code><meta name='robots' content='...'></code> with restriction directives for 
 the specified pages and posts.
Official project URLs:
https://wordpress.org/plugins/robotswhiz 
 https://github.com/maratbn/RobotsWhiz

Robots Meta Whiz

Easy way to discourage search engines from indexing only specific pages / posts with custom meta tags.

Multisite search visibility indicator vs Robots Meta Whiz