Hello!
I made new TTS integration for https://github.com/Olga-Yakovleva/RHVoice
It can be used WITHOUT any internet connection (my main concern about all other TTS services).
Supported voices/languages:
'aleksandr', 'anna', 'elena', 'irina', # Russian
'alan', 'bdl', 'clb', 'slt', # English
'spomenka', # Esperanto
'natia', # Georgian
'azamat', 'nazgul', # Kyrgyz
'talgat', # Tatar
'anatol' # Ukrainian
The engine itself is running in a Docker-container and exposes a simple minimalistic API.
Here are the links for TTS and integration component.