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.
Twitter One Click Block - Add a block button for a simple one click blocking.
WebPurify - Profanity Filter, Image Moderation and Video Moderation Services Made Easy.
Boyfairy - Your opportunity to educate right before you block someone.
CleanSpeak - Keep inappropriate content and trolls out of your community