>>37
IIRC OPL and OPL2 (AdLib, the original Sound Blaster) had only two operators per voice. OPL3 (SB16) could pair channels for four-operator voices, later versions added more operators and algorithms.
The Sega Saturn has a moderately interesting scheme which I haven't seen in other chips (though I assume the Dreamcast's one works the same). Each of the 32 channels can serve as an FM operator, but as there is no waveform ROM they all play either noise generated by the chip or a waveform from RAM which can be an "oscillator" signal or a normal sample. Each channel can itself have two FM modulation sources that are freely selectable, so you're not limited to a built-in set of FM algorithms. Each channel, including those working as FM operators, can be sent to either the output mixer (with individual pan and volume settings) or to one of the built-in DSP's 16 inputs for effects processing.
SID still beats all.