MaximeB

This plugin will check if there are some hidden meta tags with noindex and warns the author of the article. The warning is only visible for the author of the post, or the admin(s).
Features :
<ul>
<li>Check the content of a post and detect the presence of meta tags with robots/noindex in it.</li>
</ul>

Better noindex

Warns the author or admin in case of <meta name="robots" content="noindex"> hidden in a post.

SatoruHatano

PochiCheck XML SiteMap is a simple and high-performance XML sitemap generator. 
Unlike heavy SEO plugins, it focuses strictly on sitemap generation and noindex management, ensuring minimal impact on site speed. It automatically handles robots.txt integration and provides a smart auto-noindex feature based on categories or tags.
<h3>Features</h3>
<ul>
<li>Instant Setup: Works immediately after activation with sensible defaults.</li>
<li>Per-Post Noindex: Easily exclude any post from sitemaps and search engines.</li>
<li>Smart Auto-Noindex: Automatically applies noindex based on selected categories or tags.</li>
<li>Robots.txt Integration: Automatically adds the sitemap URL to your virtual robots.txt.</li>
<li>Caching Engine: Uses WP Transient API to serve sitemaps lightning fast.</li>
</ul>

PochiCheck XML SiteMap

Ultra-lightweight XML sitemap generator with per-post noindex control and automated rules.

Better noindex vs PochiCheck XML SiteMap