There is a list see below. However, instead of a list, you can do some deduction! And you might want to read this technical paper: Splunk and MapReduce A quote from the paper:
The fundamental concept of MapReduce is to divide problems into two parts:
a map function that processes source data into sufficient statistics and a
reduce function that merges all sufficient statistics into a final
answer. By definition, any number of concurrent map functions can be run at
the same time without intercommunication. Once all the data
has had the map function applied to it, the reduce function can be run to
combine the results of the map phases.
First, searches can always be run in parallel. Each indexer can be given the search criteria and return the events that match. The question: "which commands will map-reduce" is really asking "which commands do not require intercommunication of indexers"?
Splunk calls these "streaming commands," and they are defined in the Splexicon here
