A WordPress Widget is a small block that performs a specific function. You can add these widgets in sidebars also known as widget-ready areas on your web page. However these areas can be in the header, footer, sidebar, below content, and basically any other area in your theme. The available widget areas that you have in your theme will vary from theme to theme.
You can find the list of available widgets and widget areas by going to the Appearance » Widgets section in your WordPress dashboard.
There are many different types of widgets. WordPress by default comes with several widgets including categories, tag cloud, navigation menu, calendar, search, recent posts etc. Following are the widgets that I use in my page apart from what are already included.
1. About.me widget
Display your about.me profile with thumbnail, you can choose to display you profile picture or not.
2. Social media icons
A simple widget that displays social media icons linking to your social media accounts, here I choose to link to my Twitter, LinkedIn, Instagram and Facebook accounts.
3. Tag cloud
4. Twitter timeline
Display your latest Instagram photos.
New entries from any RSS or Atom feed will be updated (here are entries from professor Geniwate’s site and Lynda.com)