Descriptions of the organizations are from their websites.
The American Institute for Conservation (AIC) "is the leading membership association for current and aspiring conservators and allied professionals who preserve cultural heritage."
Conservation Center for Art & Historic Artifacts is a Philadelphia-based "nonprofit, full-service facility with experts in a range of disciplines. We have been providing conservation and preservation services since 1977. Our mission is to provide expertise and leadership in the preservation of cultural heritage."
Image Permanence Institute - "a university-based research center in the College of Art and Design at Rochester Institute of Technology (RIT) dedicated to supporting the preservation of cultural heritage collections in libraries, archives, and museums around the world."
The Library of Congress Preservation Directorate: "Preservation is a top priority of the Library of Congress. Preservation of the world's largest collection is accomplished through a broad range of activities distributed across the Library." They have an extensive FAQ page.
The National Park Service has a series of "Conserve O Grams" that " are short, focused leaflets about caring for museum objects, published in loose-leaf format."
Northeast Document Conservation Center - "the first independent conservation laboratory in the United States to specialize exclusively in the conservation and preservation of paper- and film-based collections. NEDCC provides professional conservation treatment for books, maps, photographs, documents, parchment, papyrus, manuscripts, architectural plans, and works of art on paper." Their "Preservation leaflets" are recommended resources.
APS Library from the American Philosophical Society
E. Lingle Craig Preservation Lab Blog from Indiana University Bloomington Libraries
The Fix from Smithsonian Libraries
New York City Department of Records & Information Services (scroll down to see posts)
Parks Library Preservation from Iowa State University Library
Preservation Blog from UCLA Library
Preservation Category - Library of Congress blog
Preservation Underground from Duke University Libraries
Ransom Center Magazine from the Harry Ransom Center, University of Texas at Austin
School of Conservation Blog - Books and Library Materials from West Dean College of Arts and Conservation (UK)
Stanford Libraries Blog from Stanford University
These vendors are just a sample of companies that stock supplies for repairing circulating collections items.