I’ve actually built a reminders app named Memento, which uses the same database as Apple’s app. I added functionality to delete all completed reminders for just this case lol. https://getmemento.ca. Source: over 2 years ago

I just shipped a big update for iPads in my app Memento: https://getmemento.ca. Source: almost 3 years ago

I’ve built Memento to use the same database as Apple’s reminders app, and the widget shows the date for the reminder. Check it out here: https://getmemento.ca. Source: about 3 years ago

I am planning on adding recurring notifications to my reminders app, Memento. Check it out here: https://getmemento.ca. Source: about 3 years ago

For tasks, check out Memento! It’s a reminders/tasks app I built to integrate with Apple’s reminders database. https://getmemento.ca. Source: over 3 years ago

Not exactly what you asked for but recently I've found this site with great voice generation https://micmonster.com/, it usually doesn't have that robotic accent and it's free with a 300 characters limit. I'm using it for my for my texts that doesn't have audios. Source: 9 months ago

Here is a really good Farsi text to speech: https://micmonster.com/. Source: over 1 year ago