Relevanssi WordPress plugin

It is a freemium plugin that’s available at WordPress.org. Though this plugin also can be available in two versions. Relevanssi premium & Relevanssi free version available from WordPress Plugin Repository. To improve WordPress search with a better search engine, with lots of features & configuration options. It  doesn’t come with a search widget. When WordPress site is full of content, this plugin will help to replace the default WordPress search. It is improves search functionality on any website.

Features

• Search results sorted in the order of relevance, not by date.
• When complete words don’t match try on partial words matching,
• Find documents matching either just one search term (OR query) or require all words to appear (AND query).
• Search for phrases with quotes, for example “search phrase”.
• Create custom excerpts that show where the hit was made, with the search terms highlighted.
• Highlight search terms in the documents when user clicks through search results.
• Comments, tags, categories and custom fields can be search.
• Multi site friendly plugin.
• Gutenberg friendly. 

Advanced features

• A hidden variable or plugin settings can restrict of categories and tags.
• Titles, tags and comments adjustment can be done using it.
• Log queries, show most popular queries and recent queries with no hits.
• Custom post types and taxonomies can be indexing.
• Index the contents of shortcodes.
• Advanced filtering to help hacking the search results can be have in own’s favour.
• Search result throttling to improve performance on large databases. 

Relevanssi Premium

It adds a number of useful features special for this version. It comes with a 30-day money back guarantee. It costs $99 for an annual license and $349 for a permanent license. Each license supports an unlimited number of websites.

Premium Features

• Indexing attachment content (PDF, Office, Open Office).
• Search and index user profiles.
• Search and index taxonomy term pages (categories, tags, custom taxonomies).
• Searching across multiple sites in the same multisite installation.
• The contents of attachments will be scanned and stored in a custom field.
•  Still display older posts by simply making this multiplier lower.