There are several ways to do this and the best way depends on (1) what you want to do with the list and (2) whether you want people who have given any donation ever over 500 or you just want the people where their last donation was over 500.
For instructions on how to get donors where the ANY donation was over 500, go here: http://support.blueutopia.com/hc/en-us/articles/360002917631
In this article, we'll show you how to get the donors where LAST donation is over 500.
1. Via Reports
Go to Lists and Reports / Standard Reports / Donors
Select Donors (By Amount Of Last)
This will generate a report of all donors by their amount of last. However, this report is very flexible. So now we limit it to just donors over x
Click this link for 'More than $1000'. This filters this report to only those donors where last > 1000.
Now, you can change that 1000 to anything you want.
Go to the URL. You'll see this:
You can change the 1000 to anything.
In our example, we'll change it to 499 to get a list of all donors of 500.