Filter based on the rank of a metric, so we can have Top/Bottom N of any metric. The challenge is that this would need to be independent of any sorting.
Top 10 Campaigns based on clicks, and then sort by CTR.
Currently, the best you can do is create a 'hidden Column' which is a custom (decimal) metric.
Calculation = clicks + (CTR/1000)
This still leaves you with Campaigns sorted by Clicks, and for identical Click counts, it sorts by CTR.