Assuming your field extraction is working fine and you're getting fields with numeric names, give this a try
your base search | table _time 1* 2* 3* 4* 5* 6* 7* 8* 9* 0*
| untable _time fieldnames fieldvalues
Once you get one row for each field using above search, your run searches like this
Top 10 fields based on count
...above search.. | top fieldnames
Top 10 fields based on fieldvalues column
...above search.. | sort 10 -fieldvalues
Top 10 based on sum of fieldvalues
...above search.. | stats sum(fieldvalues) as fieldvalues by fieldnames | sort 10 -fieldvalues
... View more