UUID1 and UUID4 are common. UUID1 are the ones that use machine id and timestamp. UUID4 are supposed to be randomly generated. UUID1 can be traced to a machine that created them and are sortable somewhat, UUID4s are nice because you don't have to worry if machines somehow ended up with non-unique machines (bad VM cloning can easily do that).
Versioning. The 4 says it is "version 4" in the RFC 4122 taxonomy, and the fact that the first two bits of y are "10" is meant to indicate that this is a UUID following that standard. Certain Microsoft GUIDs start with "110" in that field, and apparently there's another legacy format (Network Computing System) characterized by the first bit of y being "0". Therefore, an RFC 4122 compliant UUID will not overlap with either of these namespaces.
https://en.wikipedia.org/wiki/UUID
UUID1 and UUID4 are common. UUID1 are the ones that use machine id and timestamp. UUID4 are supposed to be randomly generated. UUID1 can be traced to a machine that created them and are sortable somewhat, UUID4s are nice because you don't have to worry if machines somehow ended up with non-unique machines (bad VM cloning can easily do that).
I would just use UUID4 for example.