Breakbot

Save yourself from googling for RTL characters, Zalgo, general unicode naughtiness, the EICAR string, and more - Breakbot makes them available for quick copying to the clipboard. With a fast search and one-click copy, fuzzing and pen testing is just a little bit easier (and no more copy-paste-type-paste-type to check if you got that RTL character copied correctly!) Just search and click the one you want to copy, or strike enter to copy to top result. Launch the popup with <Ctrl>+B. Add your own strings at https://github.com/jkingsman/Breakbot.

Screenshots from Chrome Web Store