VERY HIGHLY recommend this, I've been using it to give TTS to my moderators on streams (with their own voices and talking avatars that pop up!) and for a "60 seconds of TTS" redemption. It works REALLY well and is compatible with a lot of coding trickery to make it work however you want!
Pro Tip: Open the TTS browser source in Edge because that browser has a TON of free voices to choose from built into it!