World of Atlas is looking for the following things. Click on the link for each to learn how to submit your work:
Flash Adventures or Short Adventures for Adventure Workbook
Illustrations or Photo Cosplay
Cards for GM Flashcard Decks ($1 a piece)
Compensation to be negotiated, but rule of thumb is a penny a word for adventures up to 2500 words and $25 for non-exclusive rites to artwork. Authors and illustrators will always be credited where their work is used.