How many diodes are we talking about and what are the power requirements of the devices you are putting on them?
It's probably not a lot and relatively available 12volt auto or marine stuff should totally work.
Diodes are relatively simple they just need to withstand the amount of reverse bias voltage you are putting through them,
if your power requirements are too high they will heat up and fry just like a fuse.
A diode normally allows electricity to flow in only one direction,
by constructing a diode out of materials that illuminate using that property we have a Light Emitting Diode (LED)
... and now you are going to ask about resistors because that is probably what you meant in the first place 
