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.
Block Together - A useful tool which helps you block trolls on Twitter.
Twitterrific - Twitterific is an app that offers several functions and fun features for your Twitter account.
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.
Fenix for Twitter - A fresh Twitter experience, for Android
Moderate - Identify, mute, and block trolls in your Twitter feed