phase distortion systhesis - another form of digital synthesis from the 80's, sounds similar to FM, made popular by casio CZ series synths.
linear arithmetic - combo of sampled waveforms and analog filtering and envelopes, made popular by the roland D-50 and successors - also called Advanced Wave Modeling (AWM) by Yamaha and Digital Waveform Generation System (DWGS) by Korg, these were the precursors to the current Analog Modeled (or other clever marketing name) synths
structured adaptive synthesis - pre-sampling, this was how Kurzweil got the piano's to sound as good as they did on the K250 - basically recreating a sample of a waveform using algorithms and sine waves
and lest we not forget the oft forgotton Karplus Strong Plucked String Synthesis Algorithm, or "How to create String Instruments out of Noise" (I know how to create noise out of String Instruments!)
http://www.music.mcgill.ca/~amburns/...roduction.html 