Listr - Listr lets you explore some of the best lists on Twitter, curated across your favorite categories.
100 under 100 - For those of us that didn't get into Forbes' 30 under 30
Refined Twitter - A browser extension that improves the Twitter experience
#IWriteBecause - Every author has a story to tell, what's yours?
Blindfold - Make your life on Twitter more positive
Twitter Archive Eraser - Delete thousands of your tweets in one go —Well beyond the 3200 limit.