There are several options for free AI voice generators and texttospeech (TTS) tools、Here are a few:

1、Google TexttoSpeech: Google's TTS engine is available for free and can be used online or through various apps、It supports multiple languages and has a naturalsounding voice.
2、Amazon Polly: Amazon Polly is a cloudbased TTS service that offers a free tier with limited usage、It supports multiple voices and languages.
3、Microsoft Azure Cognitive Services Speech Services: Microsoft Azure offers a free tier for its Speech Services, which includes TTS capabilities、You can try it out with a free account.
4、IBM Watson Text to Speech: IBM Watson's TTS service is available for free with a limited number of characters per month.
5、eSpeak.js: eSpeak.js is an opensource, JavaScriptbased TTS library that can be used in web applications、It's free to use and supports multiple languages.
6、Festival: Festival is an opensource TTS system developed by Carnegie Mellon University、It's available for free and supports multiple voices and languages.
7、Voice Dream: Voice Dream is a popular TTS app for mobile devices that offers a free version with limited features.
8、Balabolka: Balabolka is a free TTS software for Windows that supports multiple voices and languages.

Some online platforms that offer free AI voice generation include:

1、Lumen5: Lumen5 is a video creation platform that includes an AIpowered voiceover feature.
2、Wibbitz: Wibbitz is a texttovideo platform that uses AI to generate voiceovers.
3、Speechify: Speechify is a TTS tool that offers a free version with limited features.

Keep in mind that while these options are free, they may have limitations, such as:

* Limited usage or character count
* Limited voice options or quality
* Watermarks or branding on generated audio
* Requirements for attribution or credits

If you're looking for more advanced features or higher quality voices, you may need to consider paid options.