Super long term lurker (since 2013), but finally have the courage to post. Haven't added myself to the spreadsheet though.
First applied for a Bulgarian ETA for the 2013-2014 year, applying as a senior in college, and was a finalist but was ultimately not accepted. Graduated and worked for a few years before deciding to apply again, also for Bulgaria as an ETA. Moved through to the next round and recently had an interview. Because there is so much interest into the questions asked, I will try and list a few. Interview was quite laid back, lasting 15 minutes from start to finish. Was told that we will find out in the end of March.
Questions:. Why Bulgaria? (In my case this was more why did I choose to study in Bulgaria while in college and learn Bulgarian formally). What do I anticipate will be the greatest difficulty in being there for a year? What do I want to do in terms of volunteer work outside of teaching? Would I feel more comfortable with a co-teacher or teaching independently? There were a few more questions, mostly ones that were highly specific, like questions about specific classes I took in college, so there is no way to really prepare for those (nor are they super helpful to post for you all, since you likely didn't take the same classes!)
With all that being said, best of luck everyone. For those applying as graduating seniors, remember if you don't get it, it's not the end of the world. Although I felt crushed when I found out that I wasn't selected in 2013, I realize now that it was really quite a good thing to happen. I learned a lot about myself over the past three years and I think I returned as a stronger candidate.