Many of us continue to use Selenium IDE and its stable working extensions. However, since the openqa site was removed/closed, there really isnt a repository of those extensions for us to go to. You could use this site, and even contribute to it to help the rest of us out, or you could try to access the old site using the Internet Time Machine (which allows us to go back in time to websites and snapshots of their content). Here is the address to start browsing that old site:
I am dissappointed in the comment for closing that site and its extensions page (even though they say some of it has moved to various archives, that's not entirely true). They claim that many of the extensions no longer work. I find that is far from the truth, and am currently (8/29/2013) using them, in thier original format, in my scripts. Even if there are a few that do not work, it is nice to have thier original code there because someone may take up ownership of the code and get it working, or the code can be used as a framework for correcting the existing code or writing new code.
To me, the issue is like like saying I cannot drive my old car, because the new cars are better. Every situation is different, and there is a strong difference between active support and referential support. That's the kind of thing Microsoft has done for 20 years + that has made most of us hate them. It doesn't take up much space and ISNT confusing and should be a choice. Leadership ... its rare. :(