electro-music.com :: View topic - first mini drone synth
Eddy Bergman.com: Synthesizer Build part-41: METALIZER by YuSyth.
Simple 555 Based Drone Synth - Sam Vs. Sound
NAND Drone - Sam Vs. Sound
Paul In The Lab: Devils Triangle Drone Synth Stripboard Veroboard Layout
Drone Synth - Layout and schematic update over the hand drawn one from earlier, based on LMNC oscillator w/filter. Curios what other ideas to add to this, I have seen capacitor switching
Evil Turtle Productions - Analog FM Drone Synthesizer
Music From Outer Space - Your Synth-DIY Headquarters