FriendFilter - Auto unfriend tool for Facebook
Listr - Listr lets you explore some of the best lists on Twitter, curated across your favorite categories.
Keep My Friends - A lightweight, personal CRM to improve your relationships
Refined Twitter - A browser extension that improves the Twitter experience
Detox for Facebook - Replace your Facebook feed with PH, HN, DN and more.
Vicariously.io - Create Twitter lists based on the follows of other users