andreyk

The WP Ya.Share plugin adds to your blog a set of buttons to save URLs of your pages/posts in popular social networks (twitter, facebook, livejournal, vkontakte etc.).
Добавляет блок ‘Поделиться’ (Ya.Share, разработанный в yandex) для сохранения ссылки просматриваемой страницы вашего блога в популярных ‘социальных сервисах’ (вконтакте, жж, твиттер и т. д.).
It uses the Yandex Ya.share API; I shaped it into wordpress plugin with some options only.
The following options are available:
<ul>
<li>locate “ya.share” block either in the content of a page/single post or in the sidebar (as a new widget);</li>
<li>select a list of preferable social networks;</li>
<li>button/link/icon for expanded social networks list, or nothing;</li>
<li>left, right or centered location;</li>
<li>above or under the content;</li>
<li>inscription language. 
Please feel free to contact me with your questions or suggestions.</li>
</ul>

WP Ya Share

Adds the Yandex 'Share in social networks' block into posts or widget to simplify saving URLs of your blog pages into social networks.

utahta

This plugin inserts social share links at the top or bottom of each post. 
For theme developers, social share links can be added by PHP code or by using shortcode. Check documentation for this use-case.
This plugin documentation can be found <a href="https://github.com/utahta/WP-Social-Bookmarking-Light/wiki" rel="nofollow ugc">here</a>.
This is the list of used social sites:
<ul>
<li>Hatena</li>
<li>Facebook Like Button</li>
<li>Facebook Share Button</li>
<li>Facebook Send Button</li>
<li>Twitter</li>
<li>Tumblr</li>
<li>Google Bookmark</li>
<li>Google +1</li>
<li>Delicious</li>
<li>Digg</li>
<li>reddit</li>
<li>LinkedIn</li>
<li>Instapaper</li>
<li>StumbleUpon</li>
<li>mixi Check</li>
<li>mixi Like</li>
<li>GREE Social Feedback</li>
<li>atode (toread)</li>
<li>LINE</li>
<li>Pocket</li>
<li>Pinterest</li>
</ul>

WP Social Bookmarking Light

This plugin inserts social share links at the top or bottom of each post.

WP Ya Share vs WP Social Bookmarking Light