Along with NYFA, CAR is known as one of the definitive aggregators of artist opportunities and resources.
Poets & Writers, Inc., is the primary source of information, support, and guidance for creative writers. Founded in 1970, it is the nation's largest nonprofit literary organization serving poets, fiction writers, and creative nonfiction writers. Our national office is located in New York City. Our California branch office is based in Los Angeles.
(But peruse the rest of the site for other great resources!)
Artist Trust is a not-for-profit organization whose sole mission is to support and encourage individual artists working in all disciplines in order to enrich community life throughout Washington State. However, they have a great collection of resource documents anyone around the country might find helpful. Peruse their resources here.
Creative Capital supports innovative and adventurous artists across the country through funding, counsel and career development services. In addition to being a significant funder of artists around the country, Creative Capital provides meaningful professional development.
A variety of articles on professional practice topics for artists-- written in a vary approachable and practical fashion. See all articles here.
Artist U is a wealth of practical resources written for artists by artists. See some of Artist U's tools here.
NYFA Source lists over 12,000 awards, services and publications for individual artists and art professionals. More programs are added everyday.