There are many such softwares. Among them, Voiceroid, AquesTalk and SofTalk are closely related to Vocaloid and UTAU.
Voiceroid series is released by AH-Software. It is based on "AI Talk" engine developed by AI, Inc. Vocaloid Yuzuki Yukari has a Voiceroid version.
AquesTalk is a talking engine (program library) developed by AQUEST Corp. Its voice is fully-synthesized; it needs no sample human voice. UTAU's default voice was made from the voice of AquesTalk. AquesTone is a singing software (VSTi plugin) based on AquesTalk technology.
SofTalk is a talking text reader based on Aquestalk. UTAU's "Yukkuri" voicebank was made from the voice of SofTalk.