SEO Tag Cloud Widget displays the tag cloud in a SEO-friendly way, using a search engine optimized html markup.
Supercharge your custom post type archives by letting visitors filter posts by their terms/categories. This plugin handles the whole thing for you!
Inserts canonical link code into header. After activation, from your WordPress Settings, change Permalinks to Custom Structure: **/%postname%/
OZ Canonical is a plugin which helps you to edit the canonical attribute easily and fast on all of your blog's pages.