MyTweetAlerts.com - Like Google Alerts for Twitter
TweepsBook - A better bookmarking tool for power Twitter users that you can use to filter, organize and bookmark tweets on your liking.
Quuu - Quuu is a curated content suggestion platform that connects to your Buffer queue, allowing you to grow a relevant social media following across your entire social landscape.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
Tweetflick - Save, organize & find Tweets to get the most out of Twitter