I know of two options. One is Melody Assistant or Harmony Assistant (found at www.myriad-online.com ) and its plugin Virtual Singer. These cost about $60 total but can be totally used free, with the only problem being that you need to quit and re-open the program regularly -- that's how I did it for close to two decades. It's a text-reading computer that can hold a pitch, so its articulation isn't the best. That said, it supports a ton of languages, and also reads IPA so you could conceivably feed it fictional languages like Sindarin. The other is www.cantamus.app . Instead of the totally artificial nature of Virtual Singer, it combines samples from actual singers. It gives you a free week's trial before charging you a monthly membership, but if you're comfortable making multiple throwaway emails at mailinator.com, or just doing a big batch of rendering, you can totally work around this limitation. It also doesn't force you to put in a credit card ahead of time. Its biggest downside is that it only supports five languages last I checked (which was several months ago). More on reddit.com

It's not AI. It's also not a massive choir. It's one baritone voice double-tracked with lots of reverb, and some "pre-verb". There's not a wide range of notes, so almost any James Hetfield wanna-be could growl this. More on reddit.com

So you want an AI voice generator, but don't want to put in any work to find the right one that works for you? That checks out actually haha, no offense More on reddit.com

id say try synthesizer V, it has a basic version that is free (with some limitations) and you can find several voicebanks that are free as well (lite versions of them). not all of them are english though, so you'll have to check that properly. there's a dedicated sub on this software with big fans - it's a whole subculture - who can help you figure it out. Solaria, Asterian, Anri and Eleanor Forte can be of interest to check (all english vbs that have a lite version). it's easy to use, you import your midi track, you pick your singer, you enter your lyrics and you have a pretty nice result. if you buy the full version of the editor, as well as the voicebanks, you can make all of them (even the non-native english ones) sing in 4 different languages, English, Mandarin, Japanese and Spanish (and the phonems are customizable so you can make other languages using the phonems of the 4 languages - i know it's been used to make russian, polish, french, and many more languages) a lot of other great softwares exist, not all with AI, but still the same principle of Midi/text-to sing. The most famous one is Vocaloid. It has a trial of 30 days and has a large catalogue of voicebanks. Again there is a sub dedicated to this software as well. it's not even a sub-culture it's a bigass culture (if anyone knows Hatsune Miku.... yeah....) Other options i know of but havent tried myself: ACE STUDIO, emvoice, CeVIO/Voisona (only 2 english voicebanks afaik and only females, but otherwise incredibly popular). UTAU/OPEN UTAU are fully free but a pain in the ass to use for the goal you have (and before anyone gets upset about it, it's not like any generative ai you know of. everything is ethical about it, the voice actors are paid and under contract. this culture has been existing since way before AI was a thing) More on reddit.com