Have you heard of the Creative Action Network? They “run crowdsourced campaigns around causes, inviting artists to build collections of original, visual, meaningful content.” I learned about it by way of Hannah (who shared their Covering the Classics campaign) and Shayna (who designed that beautiful Muir Woods poster above).
In this case, over 185 artists created over 600 poster designs highlighting natural landmarks and treasured sites in a campaign to support the National Parks Conservation Association and revive the legacy of the New Deal (and New-Deal-era posters). Anyone can submit artwork to a campaign and 40% of profits from work sold is given to the artists. What a great idea!
These are some of my favorites (you can browse by state).