In Poland we had a bus no 666 riding along the coast of Baltic sea to the city of Hel. It was quite an attraction to tourists to take a “bus to Hel” and people with at least a bit of sense of humour liked the diabolic touch to the line number. Sadly, after some backlash from religious people the operator was forced to change the number two years ago. They chose to change it to 669.

Well, I forgot to mention I am truly impressed by your list.

POL-on and RAD-on are quite specialized pieces of software that even in Poland aren’t known very well. And the names come from polish words without “-ium”, so they could not not pop up in english search results. Surely there are more niche pieces neither of us stand a chance to find easily

84 - Po - Polonium - Polish government system for information about higher education and science (POL-on) - https://polon.nauka.gov.pl/en/

86 - Rn - Radonium - Reporting system based on information collected in POL-on and other polish sources about science in Poland - https://radon.nauka.gov.pl/

“demand”