I saw mention of a Fedora Connector plugin on the dev list and some forum postings, and found it through Google at http://omeka.org/codex/Plugins/FedoraConnector. But I don't see a link to that plugin from the list at http://omeka.org/add-ons/plugins/ (or the list of .10 or .9 compatible plugins), or in the Github repository at https://github.com/omeka.
Is there a more complete list of Omeka plugins anywhere? Or at least a list of the ones that have documentation up on oemka.org?
Good point. There are two fairly recent changes to how we are handling plugins that are causing the incompleteness. First, was our move away from subversion to github for our version control. Several plugins that are no longer actively maintained were left behind in subversion. Second, was our move to a more self-serve model for others to have their plugins listed on the omeka.org/addons/plugins page. We're encouraging our developer community to register for an account on that site (unfortunately, still different from the account for the forums and wiki) so they can upload releases themselves when they are ready. That seemed more manageable than us being the gatekeepers to making plugins available, but it does open us up to this problem.
The upshot is that the omeka.org/addons/plugins page should be the most complete list of working plugins. If you see documentation for one in the wiki, but not listed there, it would be a good idea to ping the dev list or the individual developer to ask about its state. There could very well be orphaned projects out there looking for a new loving home!
I might also add that the FedoraConnector plugin was developed by our friends at the Scholars' Lab, so you might contact them about possibly updating it to work with Omeka 1.5.