I recently stumbled across a website called Art Cards Wanted, a site which allows individual creators to sell their own sketch and trading cards.

As an experiment I have joined the site and posted three cards for sale.

The cards are 64 x 89 mm on 160 GSM stock, the images were drawn in blue pencil and finished with ink and markers.

http://www.artcardswanted.com/artist.cfm?MID=5566