Yes, there are several sources of free-to-use voices that you can legally clone for text-to-speech (TTS) usage. Here are a few options:

1. Mozilla's Common Voice

• Details: Mozilla’s Common Voice project is an open-source initiative that collects and provides a wide range of voice data in various languages. The dataset is released under a CC0 license, meaning it is free for public use, including for cloning and TTS purposes.
• How to Use: You can download voices directly from their dataset here.

2. LibriVox

• Details: LibriVox provides free audiobooks of public domain books, and the recordings are also in the public domain. You can use these voices for TTS training or cloning as they are legally free to use.
• How to Use: Extract and use recordings available on their website here.