[kbolino]

FWIW it looks like Cassandra doesn't belong on this list, and DynamoDB only with qualifications.

Though Cassandra is more like quasi-SQL than NoSQL, the bigger issue is that actually the clustering key is never used for sharding. So Cassandra (today) always puts all data with the same partition key on the same shard, and the partition key is hashed, meaning there's no situation in which UUIDv7 would perform differently (better or worse) than UUIDv4.

In DynamoDB, it is possible for sort keys to be used for sharding, but only if there is a large number of distinct sort keys for the same partition key. Generally, you would be putting a UUID in the partition key and not the sort key, so UUIDv7 vs UUIDv4 typically has no impact on DB performance.