Search Form Shortcode With Post Type Filter
Adds a [search_form] shortcode that places a search box anywhere and can limit results to certain post types, such as a docs-only or products-only search.
Snippet Library
Search snippets for WordPress
Snippets that improve WordPress search: search custom fields and post types, exclude pages, redirect single results and highlight matching words. For content-heavy sites where visitors need to find things quickly.
Search Inside Custom Fields
Lets the site search also match text stored in custom fields, such as a subtitle, location or product code, not just titles and content.