Dougal Campbell

HeadMeta creates <code><meta></code> “description” or “keywords” tags for individual 
posts or pages. It can also create arbitrary <code><meta></code> or <code><link></code> tags. 
These are easily set on a per-post (or page) basis by simply adding Custom 
Fields.
See the Installation section for more detailed examples.

HeadMeta

Automatically add <link>, <meta> description and <meta> keywords to your HTML on a per-post (or page) basis.

xenice

Xenice SEO is a simple, fast, and lightweight SEO plugin designed to give you precise control over meta descriptions and keywords for every post, page, and taxonomy.
Unlike heavy SEO frameworks, Xenice SEO focuses on the essentials — helping search engines better understand your content without slowing down your website.

Xenice SEO

A lightweight SEO plugin that allows you to add meta description and keywords fields for posts, pages, categories, and custom post types.

HeadMeta vs Xenice SEO