How can I find a list of questions that used to have a bounty, i.e., the bounty has been awarded (within a particular Stack Exchange site)?
You can try this data.SE query I just threw together (remove
TOP 50 to get the full list, which will take significantly longer):
SELECT TOP 50 PostId AS [Post Link], BountyAmount FROM Votes WHERE BountyAmount IS NOT NULL
I don't think this is possible without the data explorer.