A few people have asked for more information, which is encouraging so I'll try to explain more.
The idea is not a new one, sets such as the one I'm proposing are made every so often when a group of artists get together. The results are unique and very special, but this art form/charity fund raising is not that well known. There is a market for playing cards, playing cards are collected and the 'industry' is supported by the Grand Order of Cardmakers one of the London Guilds see at the Lord Mayor's Parade every year. When and if we are able to start on the project I will apply to the guild for advise about printing and marketing.
Any and all artist medium and materials can be used the only thing to consider is how the end result will look. We will be designing playing cards, these are printed flat and on one layer. So laying and texture will be reduced to one layer in the process. That is not to say the original cannot be layered or dimensional just that it will not be reproduced that way.
Animals represented? I'm researching endangered animals and would like to find 4 far flung creatures to represent. Ideas so far are Amur Leopard, Sumatran Orangutan, African Wild Dog, Eurasian Lynx but there are so many other animals on the edge or close to it that no final decision has been made yet.
The cards do not need to fully depict the animal or an accurate drawing of it. It is the sense of the creature which needs to come across, of course to avoid confusion for card players there needs to be enough of the animal represented to make the suite identifiable but not in any particular style. So cartoons, line drawings, distinctive features, habitat with maybe just a glimpse of something identifiable will work.
I'd like the charity to be a small one where the funds raised will help make a difference. However as my artist friends are from all around the world it might be that only a larger international charity will be fair. That is something still very much under consideration.
Hoping you will join in, let me know in a comment or on face book.