The Institute for New Media Art Technology is known for developing MBROLA, Mage/pHTS and the ReVA-toolkit.
MBROLA is a speech synthesizer based on the concatenation of diphones, which was recently released as free software. There are several Swedish and Czech singing synthesizers based on MBROLA and the MaxMBROLA/MidiMBROLA instrument, which had been independently developed before the release of Hatsune Miku. The QTAU engine uses the MBROLA algorithm, with both UTAU and Festival voices.
They also extended the HTS Engine, which also powers Sinsy. This project is called Mage/pHTS and it works best with the English Festival voices, which have been converted to HTS format. The OLABuffer used by QTAU is also derived from Mage.
Finally there is ReVA-toolkit, the Reactive Virtual Agent toolkit for human-agent interaction applications. This seems to be similar to MikuMikuDance(MMD) and MMDAgent, but it is implemented using a patched version of the Godot engine.