One popular one could be 'Cinta di Ujung Senja'. It tells a heart - touching love story between a young man and a woman in an Indonesian setting with all the cultural nuances that make it special.
Yes. The Yona of the Dawn manga has ended. Although it might be sad for fans, it left a memorable impression with its engaging plot and characters throughout its run.
One common theme is adventure. Since the original story has a lot of adventure elements, fanfics often continue this. Yona and Hak go on quests together, facing enemies and exploring new lands, which strengthens their bond.
One more theme could be the exploration of the fantasy world. Writers might create new areas in the 'yona of the dawn' world, or expand on the magic and mythology that already exists in the original story. This can make for some really interesting and imaginative fanfictions.