How to get flag count for any time period I have View which displays a list of nodes with counters (flags), but the counters for all the time. How to display a list of nodes with counters (flags), for example, over the last week or last month?
Did you try to use the filter criteria : Flagged Time and eventually expose it to users?

Then you can define : 
- the operator: is equal to / is less than / ...
- a specific date or offset 

Is that what you are looking for?