What I am suggesting is somewhat like this question on Ask Ubuntu:
We can add the same type of notice to the question (it would be a community wiki, not a question).
The question would be
What free extension are there for Magento?
In my opinion, this would be quite helpful for the community to have some sort repository for a list of extension. Where each extension would be its own answer with a link to download it. This way, in time, the more helpful ones would get more upvotes which would bump them to the top.