There's peltier devices, too, which use heat traveling via different metals and maybe some sort of sorcery to generate a voltage.

Also teslacoils use a different mechanism (friction I believe), though that's a static voltage.

In theory, you could translate a magnet through a coil instead of just rotating it to produce a current. Lol spinning a ring magnet through a rounded coil could be a different way of using spinning magnets (assuming it isn't already done).