One of the top options is ElevenLabs. This AI text-to-speech software has high-quality voices in 29 languages, and its free tier includes 10,000 characters per month and three custom voices. It's good for content creation, gaming, audiobooks and other uses.
Beepbooply is also worth a look, in particular if you need high character limits. Beepbooply has four pricing tiers, starting with a free tier that offers 10,000 characters per month. It's got more than 900 voices in 80 languages and offers personal and commercial use.