.and boy, does Mashable have them in the article 50 Great Widgets For Your Blog.
Here's a few that I found interesting:
A few of these I already knew about, but I'll be honest, many of them I didn't. Of course, some of them would just clutter me up more than I'd like.MyBlogLog's Recent Readers - this Widget can easily be called a hit amongst Blog Owners; its popularity even managed to convince Yahoo into buying MyBlogLog. The widget lets you see the avatars of recent visitors to your blog, provided they're also members of MyBlogLog.
PollDaddy - Polldaddy lets you create beautiful polls in no time, and display them at your blog.
aStore - similar to AuctionAds, only for Amazon. Create a mini-store on your site and receive profit when someone buys an item through your store.
Yahoo! For Good - create a charity badge and ask for donations for a worthy cause.
However, don't be surprised when a couple of these show up here. Take a look at Mashable - it's a fine website for blog owners.