Speaking of Croatia, one must not forget to mention the Žumberak Croatian Chant. Žumberak is a region with Greek rite Catholics and there exists a book
"Timko, Inokentije, o. Crkveno Prostopinije Grkokat. Križevacke Eparhije prema Žumberačkim Napjevima. Zagreb: n. p., 1944. [iv] +  pp. Text in Slavonic, in Croatian Latin orthography." The book is an anthology of 8-tone and non-Octoechos melodies for Vespers, Mattins, and the Liturgy, the Typica, Acathist, Irmosy of feasts of Our Lord and the Theotokos, Burial. In the 8 Tones, the affinities of this chant are with the Crkveno Pojanje (Serbian style), but in the Ordinary mostly with the Carpatho-Rusyn and Galician traditions.