Here are some of the plugins I have used and that were really helpful

• Wordpress Importer:
  This plugin made importing all the old articles from Textpattern very easy. All I needed was to export them in the proper format (which was done by using this tool), install the plugin and load the xml file.
• WP-Markdown
  Markdown is one of the many plain text formatting syntaxes around that is easy to read and use.
• Responsive Lightbox
  Only one of a range of lightbox plugins available that provides support for image galleries in a lightbox overlay. Easy to use, provides inbuilt support for multiple styles (like Fancybox, Swipebox etc).