Dreamtonics

SynthV is an amazing vocal synthesizer. The voices are all great quality and sound very real. It has voices in English, Japanese, Chinese, and they are starting to add Spanish too. It supports singing and rapping. I own Vocaloid and Synthesizer V and I find myself using Synthesizer V for when I want the singer to sound like a real singer and Vocaloid for when I want it to sound like an artificial voice. My favorite SynthV voices are Solaria (female) and Ninezero (male). I recommend you look at YouTube videos of SynthV with the different voices so you can get an idea of what you can do. There are plenty of videos, and also there is a forum for users to help other users and to ask questions, etc.

Actualy it's not a free plugin/app, it's a paid product with a free voice. You've to pay the app to get the free voice.Or the contrary, you get a free app if you buy a voice.

Buy this car and get 1 free tire. :).