Nice. Handy to take a look through for those that I've not heard of (for example, Waltham thread and the two German thread types amongst a few others) and google them to see their origins, uses and specs.
Might knock up a spreadsheet from the HTML tables.
Oh, and I suspect
@MyLilMule was referring to (and thus agreeing with your thread title) the ridiculous number of threading standards, some of which are still used for no reason other than "
eh, it's what we've always used"
I mean, at a minimum, I'd like to see a "World Congress of Threading Standards", run only by engineers, pick either imperial or metric for thread dimension specifications (don't care which; they're just measurements) and have the penalty for making threads in the 'non-approved' units be a whole of life sentence of hard-labour.
That hard labour being 14 hours/day of tapping 5/16" 24 threads in 01 steel by hand, using only lard as cutting oil (every tap you break, adds another hour to your day!).