With AwesomeTTS Plus 1.37, Forvo is now part of the AwesomeTTS Plus package. And Forvo is now available in Language Tools as well.
While Forvo is limited to words only, it offers pronunciation for lesser known languages, ones which may not have good TTS offerings (such as Persian).
Also, the daily limit for Forvo has been increased to 10,000 requests / day in total, so we should rarely run into those limits, but if you do, let me know.
The forvo website has a good overview of what languages are supported: https://forvo.com/languages/