If you need more precise references to available publications and manuscript
versions, you could take a look here:
Echtra Fergusa maic Léti (Old Irish version or versions)
Aidedh Ferghusa meic Léide (modern version)
A list of texts for which no complete (critical) edition is known to us
(yet) is automatically generated at http://www.vanhamel.nl/wiki/Unedited.
It's not a very long list, but maybe you'll find something of interest.
Hope that helps!