Through the US Postal Service here are the self-explanatory ones;
Arms and weapons, including firearms, parts of arms, ammunition, and imitation arms.
Live plants and animals
Perishable infectious biological substances.
And here are the odd ones;
Articles bearing political or religious notations on the address side.
-- So no Jesus stationary?
Playing cards, except in complete decks properly wrapped.
Pulverized coca beans.
There are a few things on this list that I want to hear the story about. If anyone out there can tell me why playing cards and cocoa beans are contraband I'd love to know why.
DHL lists these;
Standard DHL prohibitions plus: Imitation and pirated products, Swastika, Hazelnuts, Peanuts, Brazil Nuts, Pistachios, Figs
--It's odd how they sneak "swastika" in with legumes and tree nuts...
Precious metals & stones
(I guess you can send your asbestos, pornography and ivory through the US Mail)
FedEx has a very long list including;
Fighting Dogs, and Racist propaganda... but nothing about playing cards.