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.
October - Visual and pseudonymous social network.
Twitterrific - Twitterific is an app that offers several functions and fun features for your Twitter account.
Supportiv - The Support Network // Any Topic-24/7-No Trolls #PeerSupport
Fenix for Twitter - A fresh Twitter experience, for Android
Kizie - Kizie is a new way to interact with Twitter