A views plugin that allows for client-side “faceted” searching.
This means that you can select an option (i.e. ‘Female’), and the results will be shortened to those who are female. it also restricts the other options as you search. You can then select another option (i.e. ‘Donated over $100) and then the results will be shortened to those who are Female and who have donated over $100. This effectively allows for negotiation with your system, giving you the most optimal results while you search.