I have recently created my first ever WordPress plugin, Append Posts is the name of it. Pretty simple but useful to create pages with specific posts beneath them. So you can for instance list all posts you have put in a category Products and tagged Free, to create a page of all free products. As soon as you add another post with that category and tag, it will be listed on the page, no need to manually add links to static pages and so on.
It uses WordPress shortcodes so you can add a shortcode like this:
[append-posts category=”tools” tags=”mentalfish,plugins” count=”3″]
See it in use on this page: http://mentalfish.com/products/lscripts/
And download it if you would like to use it yourself.