A simple web app demonstrating how text sounds in different TTS voices.
Choose from 1000+ voices from Amazon Polly (via StreamElements/Streamlabs), Google Cloud Text-to-Speech (StreamElements), TikTok, CereProc, IBM Watson, Acapela, Oddcast, Microsoft Azure Speech (via Bing Translator), and Google Translate.
Use StreamElements or Streamlabs voices for testing how Twitch.tv donations will sound to streamers who have TTS enabled via those services.
The "TTS Dossier" may have some entertaining TTS ideas for you and for reference, here's a list of characters explaining how they are pronounced (specifically by Brian).