Diodes

I'm fairly new to electronics, and I've just bought myself a lucky bap of 100 diodes.

I understand that a diode allows current to flow one way, but I don't understand why there isn't just one or what the different types are.
So, why are the different diodes of the same type, and could someone give me a quick description of the following:

capacitance diode
switching diode/fast switching diode (I guess this is just a normal diode, and one that reacts faster than normal?)
rectifiedr diode
z-diode

Thanks :slight_smile: