BlockParty - Real-time voice chat rooms from the creators of turntable.fm
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.
Block Together - A useful tool which helps you block trolls on Twitter.
Twitter One Click Block - Add a block button for a simple one click blocking.
Moderate - Identify, mute, and block trolls in your Twitter feed
Likers Blocker - Likers Blocker is a browser extension that lets you block all the followers and the people who like a specific tweet on Twitter.