Y.Kohno

This is a flexible search form widget. 
You can easily generate a multi condition search form and display anywhere as widget.
複数のカスタムフィールド、投稿タイプ、カテゴリー、タグでの検索が可能な複合検索フォームを簡単作成できるプラグイン。ウィジェットで好きな場所に設置可能。
Currently supports 
– Custom Fields 
– Taxonomies 
– Categories 
– Post tags 
– Post Type

WP Meta Search

Search form for searching through custom fields, post types, categories, tags, and free text.

websupporter

With the Plugin Profisearchform, you will be able to create search filter for your WordPress blogposts with ease! Just use the taxonomies and custom field values, you have already in use to create amazingly detailed search filters.
Features:
Fulltext Search – You can implement a fulltext search, which searches exactly the content, you want. Decide yourself, if you want to extend the search to specific custom fields, the title, the content and so on.
Select Box, Checkboxes, Radioboxes – Use these features, to place form fields, by which your visitor can restrict the search to specific terms or meta data values.
How to:
You just create a search filter by using simple drag & drop method. You can create your own search result templates and easily adjust the CSS of the outcome. After you have created a search filter, a shortcode gets generated, which you will be able to place on every page you want.
Go PRO:
With the premium version, you will have much more options:
<ul>
<li>You can place your filter as a widget everywhere on your page! </li>
<li>You can define the order, in which the results will appear. </li>
<li>You can highlight matching phrases!</li>
<li>You can use range sliders</li>
<li>You can include an order-by-field for your visitors</li>
<li>You can create min./max.-input fields</li>
<li>You can define how many posts per page will be shown</li>
<li>Instead of automatic search you can place search- & resetbuttons</li>
<li>You can restrict the search to a given term or meta data value</li>
<li>and much more…</li>
</ul>
Filter Custom Fields & Taxonomies is a five star WordPress plugin available on 
<a href="http://codecanyon.net/item/filter-custom-fields-taxonomies/6964843?ref=websupporter" title="WordPress Filter Plugin" rel="nofollow ugc">CodeCanyon</a>
More information: <a href="http://profisearchform.com" title="WordPress Filter" rel="nofollow ugc">WordPress Filter Custom Fields & Taxonomies</a>, 
<a href="http://profisearchform.com/video" title="Videos" rel="nofollow ugc">Video Tutorials</a>, 
<a href="http://profisearchform.com/help-faq" title="Filter Custom Fields & Taxonomies Help" rel="nofollow ugc">Help & FAQ</a>
Available languages: 
English, German, Serbian (thanks to <a href="http://www.webhostinghub.com" rel="nofollow ugc">webhostinghub</a>)

Filter Custom Fields & Taxonomies Light

Create search filter for your posts by using taxonomies or custom fields.

WP Meta Search vs Filter Custom Fields & Taxonomies Light