The logic behind Sets actually lives on, at least for now, within the autofill feature of Google Spreadsheets. Fill a cell or two with sample data, then option-drag (control-drag on Windows) the square autofill handle.
Yes, or if you search for "Oregano" you will notice the auto-complete for subsequent searches strongly favours herbs and spices.
I used to use this for server names. Sad to see it go.
For some reason the results from it just weren't that great anyway. It could never find sets of things that I really wanted to get.
My experience was that it started out great. I found great recommendations for books, bands, foods - even drugs. But then they tweaked it. They changed something in the settings, or maybe their index changed as they grew, and it simply stopped working. Somehow it managed to become too restrictive and too general at the same time. IMHO, sets was one of the greatest things google ever made, but it died a long time ago.