Till several weeks: GPT-2 models only in English, German, French, Chinese, Japanese, Arabic, Turkish, Italian, Portuguese, Persian, Dutch, Indonesian, Russian, Spanish, Macedonian, Serbian, Croatian, and Slovenian.
For several weeks ago: GPT-2 model in the Greek language as well. AI/Deep-Learning based, trained in an entirely self-supervised way.
Check it out at https://huggingface.co/macedonizer/gr-gpt2?text=γεια σας
I know, it is not that good as its English counterpart. Being trained only with 900 MB of Greek Wikipedia content.
However, it can be used in a decent manner for fine tunning with the writings of some famous Greek authors. I promise.