First few words for those who want to know what greasemonkey is and what wonders it can do, Greasemonkey is Firefox add-on which let you edit the way web looks and works with the help of wide variety of already available scripts and you can also write your own. Greasemonkey works simply scripts available are assigned for specific urls where it will only work and javascript change the functionality or visually the way webpage looks (it depends for what script was made)

To use Greasemonkey first you need Firefox then Greasemonkey (install) simply click on install script and Greasemonkey will do rest of the job simply enjoy changing the web your own way.

According to BlogsDNA

Whenever you will download any Greasemonkey script, your Greasemonkey Firefox add-on will automatically detects site for which that script is applicable and applys that script to the site as soon as you open it.

As promised the following are 21 most useful and best of the best Greasemonkey scripts which can change the whole user experience of any specific web application. (i chosen them from best lists out there worth 2 hours i found some new and better ones)

1. Youtube Googler (Install Script)

This script is so useful when you always want to see videos in bigger size still not full screen but moderately large so pixel don’t explode in the video. This greasemonkey script makes youtube more look like Google Videos making the video area covering most of the screen (which is obviously a user concern on that page) striping comment area and video suggestion all together on the left just like a sidebar image reference available below.

2. Youtube Alternative Video Player (Install Script)

Do you hate auto playing of youtube videos like i do? when I am searching for some videos i open 3 or maybe 4 videos at once then i have to manually pause them to see any one of them which is totally un acceptable. we have another option with this script, it replaces the stock Youtube Video Player with one that keep the video paused until ‘Play’ button is pressed but it keep buffering the video without playing them so when you press play you get already loaded video.

3. Download Youtube Video III (Install Script)

If you are everyday youtube user you must came across videos that you badly want to save on your hard disk for future usage. If yes give this script a try it will fulfill all your video downloading needs very nicely when you click on download video icon (that appears with icons under video after installing script) the download pop up will come up from where you can take video to your download manager if you want faster downloads. Linux users need to Right Click and choose ‘Save as’.

4. Youtube “Lights Out” (Install Script)

This script is eye saver I say sometimes video is too dark or too light that you literally want youtube page’s base colour to be black so you can concentrate on video and watch it properly without hurting your eyes. well now you can do something about it this script gives you a little button to switch the lights off and watch the video easily when you click on ‘Lights Out’ button everything on the page (except video) turns dark gray when you click again everything turns Black. When it’s too dark and you can find ‘Lights Out’ button don’t panic clicking anywhere on the page will turn lights on.

5. Flickr “Lights Out” (Install Script)

Flickr Lights Out works same as ‘Youtube Lights Out’ so you can watch pictures easily when lighting condition is not all good matching with picture the only difference is ‘Light Out’ button is on top of picture.

6. Text Areabackup (Install Script)

Remembering everything you write on the web is not as easy as it sounds this script gona ease your mind. Text Areabackup work as a remembering machine while you browse the web and putting your emails, website addresses in short everything you write will be save in a virtual memory of this script. (Note: this script don’t work with Gmail)

7. Google Image Relinker with Mouseover (Install Script)

This is one of my favourite script because of its function and how much ease it gives when you searching for images in Google Image Search. Normally you when you search for images you have to do a lot of mouse clicks to get to the actual image but now things are a little bit interesting when this script is installed you just ‘Mouse Over’ or we say ‘Hover’ over any image thumbnail and see the image preview first then click on it and you get to the image directly instead of clicking again for ‘full size image’ its mean only one click and you get the image. How sweet!

8. Google Account Multi-Login (Install Script)

I am using more than two gmail accounts one for work purpose and one my personal so i had to find this script for multiple account usage at once because signing out and signing in again isn’t as easy as it sounds and waste bit of time too. After installing script your ‘Sign Out’ will turn into drop down box with a couple of options there you can add as many accounts as much you want and switch them with a single click of mouse.

9. GoogleTagCloudMaker (Install Script)

GTCM is really very useful script when you can’t decide proper keyword of your desired search result. It makes a tag cloud at your right pane with suggestion of many relevant keywords to choose from this also help you finding related search results of what you are looking for.

10. Google Ads Remover+ (Install Script)

Sometimes ads are really annoying specially when your connection is slow and web page stuck when it’s loading ads. Now you can remove Google ads from any website you want for faster browsing as a side note I won’t recommend disabling ads because sometimes you really find good resources and considerable product offers out of them so if you have no problem with them then leave as they are. Other usage of this script is to configure it to disable ads from a specific url not the whole web just like i did it with my website so I don’t accidentally click them and penalize for click fraud.

11. Google Image Auto Pager (Install Script)

This is another script for google image search to make searching images easier. Google image auto pager makes ‘image search page’ advance by giving you option to load next set of images on the second page loads on the very same page where you start. When you search for some image you get a lots of results when you are done with first page simply ‘Double Click’ any where on the page to load next set of images doing this again will stop the loading process.

12. Disable Text Ads (Install Script)

I know I know sometimes text ads (Contextual ads) are so much annoying that you badly want them not to disturb and make hurdles during browsing. This script work simply you install it and get rid of text ads forever. Currently this script is removing ads from following Advertisement networks “Vibrant Media (IntelliTXT), AdBrite, Infolicious (lingoSpot), Kontera, Linkworth, EchoTopic, Targetpoint and MediaText.”

13. Pre-fill Comments (Install Script)

Pre-fill Comment is really a life saver script because the one’s who comment on blogs, products or webpages will love this script for life. I know no body likes to write his name, e-mail and url everytime he want to visit a new blog then how about just pressing ‘Alt+C’ and the fields will be filled automatically sounds very easy, yeah obviously it is.

14. LookItUp2 (Intsall Script)

This script is more than just a greasemonkey script because when i first saw this i never believed just a script can do this much. You can add whichever website in it to look up what ever you want to just like add wikipedia and search for ‘Al Pacino’ now you get information without exploring all over the website. Many search sources comes when you install the script and you can add many more according to your choice i prefer you to visit this script’s homepage so you know all information about it because features are vast and I can’t review it all here.

15. Digg Friend Easier (Install Script)

Making your digg profile healthy is all about friends, and users becomes friends when you regularly digg their submissions. This script make things a lot easier than you can ever think now you can digg your friend’s submissions in bulk you do it everyday and they’ll consider making you mutual friend someday. When you install this script submission pages ‘/friends/submissions’ and ‘/friends/shoutsin’ will be having ‘digg it’ shortcut under every submission so you just click on it and ajaxly it will be dugg instantly. Keep on digging ‘easily’

16. Always Open New Windows in Digg (Install Script)

If you are a regular digger spend hour or two just digging then your your left hand always picking up CTRL key (there are also other ways to open new window except holding CTRL key while clicking link) to open external links in new window well now you don’t really need to worry about this problem just install this simple little script and click the links in digg they’ll open in new window always.

17. Advanced Search Options on Digg’s Search Forms (Install Script)

Sometimes while searching on digg you get a lot of irrelevant results but now that wont be a problem any more with this tiny script search forms are advance more than ever and have a lot of options that a search form needs. you can also customized the way search results show look the following screenshot for reference.

18. SU Visual Editor Plus (Install Script)

This script enhance the way your text editor of your stumble upon page looks and works. Installing ‘SU Visual Editor Plus’ won’t do such any wonders but it can increase functionality such as increased width, increased height, background colours matched of the editor etc

19. Stumbleupon Avatar Bubbles (Install Script)

This script works so simple yet interesting and i thought every stumbler would loving using it. After installing SU Avatar Bubbles you get option to see Avatar images bigger when you hover your mouse over them so you dont need to open profile then click profile image to see actual size of the avatar.

20. AJAX Twitter Refresh (Install Script)

If you use twitter from web then you won’t be able to see new tweets unless you refresh the page. After installing this script your twitter page will be automatically refresh every after a minute (70 times per hour) this twitter page refresh scripts is better from others because you won’t notice when page refreshes actually its ajaxly refreshed.

21. Endless Tweets (Install Script)

If you are a die hard twitter and use to tweet everyday and explore people twitter timeline then this script is surely for you. The script automatically loads next set of tweets when you scroll the bottom of the timeline page unlike you click ‘Older’ button and read the tweets on second page. Endless Tweets saves a lot of time and preloading of tweets is also very fast.

Some other resources for the betterment of human kind

If you are interested in making your orkut profile more interesting you should visit this post at BlogsDNA where he tells you how to theme your orkut profile and some good orkut themes too.

If you don’t like using Firefox (i doubt though) you should visit this post at Techie-Buzz where you know how to use Greasemonkey Scripts with IE, Opera and Safari.