Thomas and the U.K. Trip & Thomas Number 1 (found Japanese "Thomas the Tank Engine" crossover TV special and music video; 1993)
Thomas the Tank Engine has had many specials, and most believe the first was Thomas and the Magic Railroad. However, in 1993, the true first Thomas special aired, a crossover entitled Thomas and the U.K. Trip, featuring characters from the Japanese show, Hirake! Ponkikki. The characters from the Japanese show visit the Island of Sodor where Thomas and his friends live, and then the "real" UK to see real steam engines. The special was never released on VHS, however, it is most likely that it was recorded by a home viewer, as the whole special is on YouTube.
Another rare Japanese Thomas artifact is the song "Thomas Number 1." It is so obscure that it is not listed in the songs category of the official Thomas the Tank Engine wiki. It is as yet unconfirmed if this is a real Thomas music video, or just an fan-made video. If it is real, then it is actually the first Thomas the Tank Engine music video, as it only has clips from seasons 1 and 2. (The song currently credited as the first is Thomas' Anthem).