[GreatScott] points out that there are other useful diodes and, in particular, he posted a video covering Schottky and Zener diodes. These special diodes have particular purposes. A Schottky diode ...

They have none of the special skills you’d find in tunnel, Gunn, varicap, Zener, and avalanche ... to C1 will appear at both the anode and cathode of the diode, and will make it through C2 ...