Vocalist.ai is a good option, letting you transform raw vocals into polished tracks. It spans a broad range of genres, and you can make male and female versions of a song, and add rap verses. The service is highly customizable, with high-quality conversions and royalty-free output, and it's designed to be easy and convenient for creators.
Another option is Revocalize, an AI voice generation service that's designed to be all-purpose. You can create your own AI voice or select from a library of licensed voices, and you can convert one voice to another to match different styles like rock, pop, country and more. Features include real-time auto-tune, professional voice modulation and a range of creative voice profiles. It's geared for sound engineers, producers and artists.
Lalals is another good option, offering voice changing, cover creation and original song generation. With more than 1000 AI voices, including celebrity voices, you've got a lot of options. The service spans multiple genres and languages, and commercial use requires a paid subscription, but it's a good option for musicians who want to try out different styles.