OSX Network is provided by Jeff Biggus and has a wonderful list of applications for OSX. OSX Network is also known for its extensive OSX development articles listing, to be found here.
Here is the page that lists all the registered QuickLook plugins. At the time of this writing, you can find plugins for the following file formats:
- Brainsight QuickLook Generator - Supports medical image file formats
- Colorxml-QuickLook - XML QuickLook
- EPSQLPlugIn - EPS files
- flv.qlgenerateo - Flash FLV files
- Folder.qlgenerator - folder contents
- illust.qlgenerator - Illustrator files
- Mac2SpecQLPlugin - Spectrum SCR file
- QLEnscript - Programming code
- Quickcomic - Zip/cbz file
- QuickLook Script - AppleScript source
- TextMate in QuickLook - Renders QuickLook previews using TextMate highlighting
- Zip.qlgenerator - zip file contents
- ZipQuickLook - Zip file
Keep the URL in your bookmarks to check the updates.
Another site that has a list of QuickLook plugins (the two overlap a lot) is hrmpf.com. The page also has screenshots. Here again, the list seems to be updated quite often.
And if you want to create you own plugin, here is Apple's developer docs.
Apple does not seem to have a section dedicated to QL plugins on its download page...