Cepstral sells several voices that can be used by speech synthesis engines. It is possible to test a given voice prior to buying it.
Supported Language(s): US English, UK English, Canadian French, Americas Spanish, German, ItalianDownload Size (Mb): N/A
System Requirements: N/A
Price: Voices range from $10 US to $45 US
Website: https://www.cepstral.com/en/demos
Developer: Cepstral LLC
Download: https://www.cepstral.com/store/