Block Together - A useful tool which helps you block trolls on Twitter.
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.
WebPurify - Profanity Filter, Image Moderation and Video Moderation Services Made Easy.
Moderate - Identify, mute, and block trolls in your Twitter feed
CleanSpeak - Keep inappropriate content and trolls out of your community
Twitter One Click Block - Add a block button for a simple one click blocking.