How very interesting & 'Selective', I mean, not just stamps w/ Mountains, but stamps depicting 'Mountain Climbing'. Good luck because if any Discussion Group could help you find such 'rare avis', This is the Group! Happy hunting & Welcome to this group, Harry
Harry, you are correct that this very tiny niche isn't likely to yield much interest or volume. I did find a stamp from Canada that fit the mountaineering criteria. https://postagestampguide.com/stamps/17665/mountaineering-2006-canada-postage-stamp
Hello xiantaner: The only mountain climbing stamp I know of and have is France, Sc. 804, 75 francs, issued July 7, 1956. If there is a checklist for mountain climbing, the American Topical Association (ATA) is the organization that would have it. Membership is required to receive their checklists, however. Membership in ATA is a good thing if you are a topical collector. See this site: http://americantopicalassn.org/home.shtml Don
Hello Xiantaner, I would also like to start a topical Mountain Climbing stamp set- if you find additional information please let me know!