It's Germany and Turkey.
In a press release earlier this year[0], BioNTech described their relationship with Pfizer and they listed the countries it covers. Also, for China they have another company instead of Pfizer.
Why Germany and Turkey, you may ask? Well, the inventors and founders of the company are Turkish immigrants to Germany. So they are able to give the vaccine on special terms to the country they came from and the country that made them. To be honest, Turkey is extremely lucky that they feel like helping out the motherland. Thanks to them, Turkey has abundance of the vaccine and probably at a good price.
[0] https://investors.biontech.de/news-releases/news-release-det...