I like this for doing a conjunctive filter by Category and Tag. For example, to search for all articles tagged with “WordPress” in the “Snippets” category. See the below-refenced blog article by me for more information. From the Web site: …
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Discovered this via Bill Erickson blog post of October 25, 2018. He uses it for Related Posts functionality. Pricing: $79, $149, $299 for 1, 5, and unlimited sites. Standard, Pro, Pro Plus. Pro and Pro Plus include all Pro extensions. …
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ME: With this plugin you can customize WordPress search to search in Post Meta, Author names, Categories, Tags, or Custom Taxonomies via admin settings. You can control the default behavior of WordPress to search in the post title, post content, and post excerpt.