Thumbnailer is a plugin for WordPress that allows you to generate thumbnails of images “on the fly” i.e. the script will create a thumbnail of the original image as it is viewed.
Header Image Rotator rotates your blog header images.
WP2HTML lets you export your blog entries as a single HTML file. Adds HTML file to ZIP archive. Also check out Gravatar (and userpics) on the same page. It allows you to generate a gravatar URL complete with rating, size, default, and border options. See the documentation for syntax and usage. It also shows LiveJournal userpics in comments.
Random Link Button plugin give you the ability to place a button on your blog that directs the user to a random site every time it is pressed. The random link is chosen out of your WordPress blogroll, so you can make use of your existing links.
Blockquote Cite allows you to add easily cite references when using the blockquote tag. To add a reference, simply use the cite element and then enter the URL of site the content was quoted from. If a logo is available for that site, it will be displayed. Otherwise a text link will be used.
Force User Field Registration forces new users to register additional fields (such as first name and last name).
Check Email Posts uses the inbuilt cron to check for posts-by-email every hour.
WordPress Comment Spam Stopper stops comment spam by adding an additional question field that a visitor must answer before the comment is submitted.
StripTease is a simple filter that strips fragment identifiers from WordPress’s default teaser links so that they link to full posts. It doesn’t require any configuration, and it works with WordPress’s default querystring permalinks, as well as its rewrite-based “pretty permalinks.”
URI Index Remover removes â€œindex.phpâ€ from any URI ending in â€œindex.phpâ€. It does an instant redirect to the non-index.php equivalent of that page.