Twiangulate - Analyzing Twitter's hidden networks for influence and recruitment.
Ushahidi - Ushahidi gathers data from various sources and reports incidences around the world in real time.
ExportData.io - Export Twitter data for your business needs.
360social - 360social is a browser plugin that shows the social footprint of the people you want to connect with right inside your browser.
Followerwonk - Followerwonk by Moz is a Twitter analytics tool to help companies better understand their Twitter followers.
AwesomeHunt - Community-curated lists of learning resources on any topic.