You can run a custom query for Gift Amount is greater than $ and gift date is between the first and last day of the month you want to see or whatever time frame you need (like this year if you want to see all givers who've given above a certain amount so far this year). You can add more filters like choosing specific funds as well. Here's what the query looks like when you're setting it up. Hope this helps! 

Jason, this is a good idea so, please add this as a request in the Ideas for Ministry forum or vote on the request if it is already there.