My Web habits differ from yours. Therefore, the Greasemonkey scripts that I find useful may differ from your idea of a useful Greasemonkey script. I use many of the same sites you likely visit, however, so perhaps you'll find these useful as well. If not, let me know which scripts you use in the comments below. Share and share alike, I say.
Before we get to my favorite six scripts, let's back up a bit. If you don't know a Greasemonkey script from Shinola, start with my post on how to get started with such things. If you still find yourself interested, read my post on how to manage your scripts.
I spent some time this week combing through the numerous scripts at userscripts.org, the main repository for Greasemonkey scripts. I found that many scripts were outdated or just plain useless, but there were some that aided my Firefox experience. Without further ado, they are:
This script lets you customize the Google search results page by splitting it into multiple columns and removing certain elements such as Sponsored Links. After installing it, you can access its settings panel by clicking on the gear-icon button in the upper-right corner of a Google search results page and choosing GoogleMonkeyR settings. From the settings panel, you can choose to display results between one column and four columns, select a background color for the shading behind each result, and also choose various elements you'd like to remove from the page.
YouTube Auto Buffer & Auto HD & Remove Ads
This script places an Autobuffer Options button below YouTube's video player. It lets you disable autobuffer and autoplay options so that videos won't play until you hit play (autobuffer) or begin playing right away (autoplay). You can also use the script to play videos in HD by default, choose a volume level for all video, and hide in-video ads and annotations.
Facebook Ad Remover
Not a fan of those Sponsored links in the right-hand column of your Facebook Newsfeed? Then get rid of them with this script. It takes out the Sponsored links from your Newsfeed (but not from your Facebook page or those of your friends) along with the items above the Sponsored links such as birthday announcements, events, and requests.
I don't want to Install Google Chrome
If you and Firefox are happily engaged in a monogamous relationship, then you don't need Google tempting you to Install Google Chrome on its homepage. This script gets rid of the box that offers "A faster way to browse the Web."
For Craigslist shoppers, this script is a must. Instead of browsing for something and needing to click through to each listing to see its picture, this script splits the listings page into to panes. The left pane shows the listings with inline thumbnails. Hover over a thumbnail to see a larger version of the picture in the right pane. Similarly, click on the truncated description in the left pane to read it in full in the right pane.
Disable Text Ads
I encounter sites that use those annoying text ads less frequently today than in the past, but they are still out there. You know the ones: a double-underlined word will pop up an annoying context-based ad (sometimes with video!) from Vibrant Media (called IntelliTXT) or another online advertiser. This script blocks these ads.
And as a bonus, here is a broken script that I really want to work. It's called Whom to Follow and corrects an annoying grammatical error on Twitter, replacing the Who to Follow header with the correct construction, Whom to Follow. I believe I speak for all English nerds and grammar Nazis when I put out the clarion call for this script to be updated!