The American Philatelic Society is the largest, nonprofit society in the world for stamp collectors.
The American Philatelic Research Library is the largest public philatelic library in the United States. Its holdings include many of philately’s classic periodicals, and it receives more than 400 current periodicals from around the world.
The American Revenue Association is the largest, oldest, and fastest-growing national or international society devoted to revenues, tax stamps, stamped paper, telegraph, and railroad stamps, and general non-postal back-of-book material.
The Meter Stamp Society is dedicated to the collection of postage meter stamps, topical slogans on postage meter stamps, computer postage (CVP), framas, photostamps, and similar items.
The mission of the Postal History Foundation is to promote an appreciation of stamp collecting and postal history through the preservation of philatelic and postal history collections, literature and documents, and the enhancement of youth education using stamps as teaching tools.
The Revenue Society is an international society for collectors of worldwide revenue stamps and documents that promotes the research and display of revenue stamps and their associated documents, and publishes a quarterly journal. The Society also encourages members to exhibit their collections at regular meetings in England as well as at National and International Philatelic Exhibitions.
The largest listing of U.S. local revenue issues anywhere is at the U.S. City and County Revenue Catalog. Organized by state. Many illustrated.
The aptly named State of New York Stock Transfer Stamps has high-resolution images of over 300 varieties of these stamps. Content is nicely indexed, with examples of key identification features, and usage examples.
Rob Henak’s State Drug Tax Stamps site is a gateway to controlled substances tax stamps from the lawyer who invalidated Wisconsin’s controlled substances tax!
Eric Jackson is the world’s leading philatelic firm dealing in United States and Canada revenue stamps and related literature.
The Catalogue of the Crawford Library of Philatelic Literature at the British Library contains indexes to, and searchable documents digitized from the major philatelic library built up by the 26th Earl of Crawford. This library was willed to the British nation by Crawford upon his death in 1913. Some documents refer to U.S. state revenue stamps.