StampPrinters.info is a philatelic resource that chronicles the history and work of postage stamp printers worldwide from 1840 to the present. It offers detailed information on the production processes of stamps, lists of printers by country, and insights into the evolution of stamp printing, making it an invaluable tool for researchers and collectors interested in the technical aspects of philately.

FamousStamps.org explores the world's most famous and valuable postage stamps, offering insights into their postal history and the unique circumstances that have made them noteworthy. The site includes a comprehensive list of stamps like the Penny Black, Inverted Jenny, and British Guiana 1c Magenta, among others, detailing their stories and significance in philately.

Lee's Illustrated Stamp Listopedia, hosted at Filbert.com, appears to be a comprehensive philatelic resource offering a wealth of information about stamps, including online auctions, directories of auction houses, and special-purpose stamp varieties. It serves as a valuable tool for both novice and experienced collectors looking to deepen their understanding of philately through a diverse range of topics and resources.

Filatelia.fi provides a comprehensive worldwide list of philatelic experts, focusing on those who have back stamped or hand signed postage stamps, or issued certificates, mainly before 2000. It includes about 2000 expert names and over 700 scans for deciphering expert marks, serving as a valuable resource for collectors to verify the authenticity of stamps and avoid forgeries.

Professional Stamp Experts (PSE) specializes in authentication, grading, and certification services for United States, U.S. Possessions, Confederate States of America stamps, covers, postal stationery, and back-of-book material. PSE is known for its integrity, offering a guarantee that stamps are genuine and graded according to PSE's standardized philatelic grading scale.

The Sunday School Stamps collection at Muba.eclipse.co.uk is dedicated to exploring the unique niche of stamps and albums specifically created for Sunday School attendance and activities. These items include traditional album stamps, attendance card stamps printed on card yet still perforated like traditional stamps, and serve as a historical insight into the religious and educational use of philatelic materials.

World Webtimbres offers an extensive exploration of global stamps through various themes such as history, inventions, art, culture, and more. The site provides a thematic journey through stamps, showcasing their role in depicting the world's cultural, technological, and historical milestones.

Philarz.com focuses on joint stamp issues, highlighting stamps released by two or more postal administrations to commemorate common events or anniversaries. The site offers a comprehensive catalog of such issues, detailed descriptions, and images to philately enthusiasts interested in the collaborative aspects of stamp collecting.

2-Clicks Stamps is an extensive directory designed for stamp collectors, offering a wide range of philatelic resources including guides, articles, and a database of classified philatelic web pages. It serves as a comprehensive online guide for both new and seasoned collectors, providing insights into stamp values, history, and collecting strategies.

ForeverStampPrice.com provides detailed information on the current and historical prices of USPS Forever Stamps, including rates for one ounce, additional ounces, and various types of Forever Stamps. It also offers insights into postage saving tips and updates on rate increases.