It would be useful if Elasticsearch could generate automatic snapshot names. This would be a POST to the repository instead of a PUT to a snapshot name.

curl -XPOST localhost:9200/_snapshot/my-repository

The name could be generated by incrementing a number (1, 2, 3, etc), getting the current timestamp, or generating a flake id.

To organize snapshots in a repository, the POST action could accept a prefix parameter.

curl -XPOST localhost:9200/_snapshot/my-repository?prefix=my-index -d '{"indices":"my-index"}'