See https://www.mongodb.com/docs/manual/reference/operator/aggregation-pipeline/#db.aggregate---stages for a list of the stages.

This is part of the 6.3 epic to add support for "V2 Scope: Cluster Connection Health Metrics" by ensuring all the database-only stages are present in the library of aggregation stage operators. This will ensure $currentOp is suggested by our autocompleter where database stages are enabled (currently only in VSCode playgrounds).

NOTE: this requires updating the stages library in all of the products.