VOCALOID - VOCALOID is a singing synthesizer.
Synthesizer V - Synthesizer V: at the Forefront of Singing Synth
Chipspeech - chipspeech is a vintage-style speech synthesizer which recreates the sound of famous 80's voice synthesis chips.
Emvoice One - Vocal creation and arrangement tool unlike anything on the market.
CeVIO Creative Studio - CeVIO Creative Studio is a software suite that provides you audio creation and digital signage tools.
Jussi - Jussi is one of the top modern singing synthesizing software that emulates male voice vowels in a unique way.