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.

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.

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.

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.

PhilaMercury is an online, open-access database dedicated to United States covers, offering a platform for collectors and dealers to upload images and descriptions. It serves as a resource for research and collection documentation, and includes a public discussion forum for philatelists.