Copy Buddy is a very simple Notepad add-on for Firefox. It opens in a pop-up to create, edit, and save notes. You can also expand and shrink editing area.
Tab Finder is a Chrome extension to find any tab in real-time using keywords. Enter the keywords, find the tab, and press Enter key to jump to that tab.
Tab Ninja is a Chrome extension to close all tabs that are currently loading, playing audio, muted, pinned, have same domain, etc., in two mouse clicks.