Third Best Way to Find New Ubiquity Commands
The two best ways that I have found so far to find new Ubiquity commands are the Ubiquity In The Wild Mozilla wiki page, and there is the Ubiquity Herd. But other than these two resources there really isn't another, and you are left with using a search engine like Google. So I have created a new Mixx community for Ubiquity for anyone that wants to contribute, where everyone can find links related to Ubiquity and new commands for it. Of course there is also the ability to vote for links, tutorials, articles, etc.. so come check out the Mixx Ubiquity Community.
If you don't already use Mixx I highly recommend it, and if you have an account, then join the community and contribute by using the 'ubiquity' tag, or joining the community and adding the link to the Ubiquity Mixx community.

@erikvold