Yes Hi Martin Ryan, I suppose it is taking a very broad view to call any song that encouraged people to think of Ireland as a country and people who should be free of domination by a stronger neighbour but such are often included in the "Rebel Songs" catalogues.
As "Fiolar" suggested I believe that there must have been many, many "rebel" songs composed by the old travelling Bards that were never translated much less written down, which were also comments on the times in which they were written. This was how they made a living I understand. Many , perhaps most, have probably been long forgotten.
I am not a collector of old songs much less a scholar but I have memories of learning several "poems" in my schooldays that had alternate verses in English and Irish that also professed alternating sentiments towards the rulers of the times in which they were written. Have you come across any of these ?