The Franklin Oscillator
The Franklin oscillator is a little strange and not immediately obvious how it works:
The following helps a lot:
(source: www.radiosparks.com/images_d/Franklin Oscillator.png)
So positive feedback at parallel resonance (0 degrees phase shift).
The next image is a transistor version:
Here is a rationalised (long tail pair) FET version:
Still it takes a leap of faith to get to here:
But at low voltages most of the biasing components can go!