World Flag is a free WordPress plugin which enables your blog authors to use country flags easily inside their posts, pages and other shortcode supported areas. So if you are looking for such kind of plugin then simply install and activate it.
Default WordPress search only allows your website users to search anything locally on particular website. If you are a network administrator you can easily enable a Global Search that searches the given keywords in all subsites of your multisite network by post title, post content or post author.
LinkedIn targets business professionals, it helps people who are looking for job and business opportunity to discover inside connections. This article suggests three plugins that helps you integrating your LinkedIn profile in your WordPress site.
Inserting BuddyPress specific data in posts, pages, widgets etc means you can display specific BuddyPress stuff wherever you like in your website simply by using shortcodes.
Creating FAQs for a website, product or service etc is a common thing. Most of the WordPress users create a simple page showing a list of FAQs in there. Today I encountered a fine working WordPress plugin by norcross specially created for adding and managing FAQs in WordPress. So use it because it gives a better experience than creating simple WP page for FAQs.