Is there some reason new versions of UUID keep appearing? It seems like the desired properties are never quite achieved so new ones appear later. Is there a table with UUID version across the top and characteristics down the side, so I can see the differences and pick one that fits my needs? That might also help to explain why there are so many variants.

Unless you have specific needs, the only type of UUID you should care about is v4.

v1: mac address + time + random

v4: completely random

v5: input + seed (consistent, derived from input)

v7: time + random (distributed sortable ids)

As someone who only cares about v4, I periodically wonder why don't I just use fully random 128-bit identifiers instead (without the version information).

UUID v4 isn't large enough to prevent collisions, that is why segment.io created https://github.com/segmentio/ksuid which is 160bit vs the 128bit of a UUIDv4.