There are many interesting topics for oral presentations. The topics depend on your students’ level and interest. To begin with, may be it would be a good idea to ask your students what they would like to talk about. In this way, their motivation and commitment to the preparation and participation to the oral presentation will be increased. From the suggestions they would give you, you could choose one and use it for an oral presentation topic. Then, any common discussion topics linked to sports, hobbies, interesting facts, odd jobs, trips, dreams, social/political issues, etc. can work when well presented to the students.
I hope that my thoughts will help you somehow.