It's not really an app, but rather a plug-in for Google Chrome on your PC:
https://chrome.google.com/webstore/detail/etsy-favorites-cleanup/hhnmhhkkmdjccfloclmpgkoolebdpgpd?hl..."Etsy Favorites Cleanup" $2.99/year. Click once and unfave a whole page. Worth every penny of the $3 for those of us who have OCD about cleaning out our favorites, haha.
There are a couple of free ones from the developer (can be checked out under the "related" tab). One is for clicking (opening) many items at once for "clickathons." It does not work on incognito pages, which is how I would use it.
There is another for $15 that is "unfave/fave" a whole page at once. Handy if you do a lot of that.
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On a related subject:
Etsy relevancy cares about "recent activity" and not number of hearts on an item. JFTR : ) That's the reason for the unfave/fave so that even on items that are already favorited, they get unhooked, so to speak, and rehooked. The re-favoriting is considered "recent activity."
Of course, nowadays, Etsy supposedly can tell where the activity comes from and penalizes, to a degree, favoriting and clicking directly from team threads. So some teams have developed clicking and favoriting games that are more "organic."
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