1Password - 1Password can create strong, unique passwords for you, remember them, and restore them, all directly in your web browser.
ilo - Premium Twitter analytics
ClockTweets - Schedule, analyze, and stalk challengers on Twitter
LessNoise - Recommendations on who to unfollow on Twitter
Tweetastic - Better Twitter analytics, scheduling and more
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.