Two of my favorite websites are MacUpdate and Version Tracker. If I need a piece of software to do a specific task, or if I think a piece of software is out of date, these sites are my first stop. They keep track of links to all sorts of shareware, freeware and commercial software. Both have search engines that are both fast and efficient. Both have separate listings for Mac and iPhone, and Version Tracker even has a page for Windows software.
Typing RSS into the search field on both gave me the following listings:
For general searches, MacUpdate is my favorite, but it never hurts to check both sites. You might find different suggestions in each site. Another plus factor are the mini reviews post by actual users. Some need to be taken with a grain of salt, but most are pretty reliable.
I know I've written about these sites in the past, but they remain in my favorites list. Check them out. You might like them, too.