What are some natural sources for cyanide

It can be found in cigarette smoke, plastic, cassava, Lima beans, and almonds

Cyanide is found in very many places, some we would never expect. Here's a list of what I know has traces of or has cyanide in it.

Paper.
Textiles.
Plastics.
Bug Killer (Cyanide gas is used to exterminate pests and vermin in ships and buildings)
Artificial Nail Remover. 
Any sort of acetonitrile-based products.
It is used to remove gold from it's ore.
It is present in the chemicals used to make photographs.
Cigarette Smoke
Vehicle Exhaust
Spinach.
Bamboo Shoots.
Almonds.
Lima Beans.
Miscellaneous Fruit Pits.
Tapioca.

These are just what I know of, I'm sure there's many more.

Hope this helped! :)

Contained in chromosomes which are located in the nucleus of the cell.