ilo - Premium Twitter analytics
ClockTweets - Schedule, analyze, and stalk challengers on Twitter
Seekmetrics - Instagram, Facebook and Twitter Analytics.
LessNoise - Recommendations on who to unfollow on Twitter
Accountanalysis - A tool to evaluate Twitter accounts
Secateur - Use Secateur if you want to temporarily or permanently block or mute (or both block and mute) a Twitter account and all its followers.