Here its a list of Google Chrome, firefox, Mac Tools, Extensions & Apps that I have collect during my learnig process! 
Hope you find something useful. I will add some more soon and if you know any others not listed or have any tips. Please share with us!
Postman Supercharge your API workflow with Postman! Build, test, and document your APIs faster.
OneTab Save up to 95% memory and reduce tab clutter
Magic Actions for YouTube™ Auto HD, Ad Block, Cinema Mode, Mouse Wheel Volume Control, Screenshot…
JSON Formatter Makes JSON easy to read. Open source.
JScript tricks You can trick any page! Add your own JavaScript (powered by JQuery) and/or CSS to any page.
Git Cheat Sheet Handy Git cheat sheet for easy access to common Git commands and terminology
geojson.io Edit files on GitHub and elsewhere in geojson.io
Flowhub Peer-to-peer full-stack visual programming for your fingers
Screencastify (Screen Video Recorder)
SnappySnippet Easily extract CSS and HTML from selected element. Then send it to CodePen, jsFiddle or JS Bin with one click.
Simple Blocker block distracting or annoying websites and boost your productivity.
Shdr Shdr is a live ESSL (GLSL) shader editor, viewer and validator powered by WebGL and built by Thibaut Despoulain (BKcore).
WaybackMachine the extension uses web.archive.org’s internet archiving Wayback Machine to view the current website you’re on in the year and month you specify.
WebRank SEO Website Ranks(Alexa Rank, Compete Rank and Quantcast Rank), traffic graphs, social statistics, pages indexed and backlinks in various search engines(Google and Bing).
Open SEO Stats quick access to Geo IP Location, Whois, Alexa, backlinks, indexed pages and more.
CSS Shapes Editor
ColorPick Eyedropper An eye-dropper & color-picker tool that allows you to select color values from webpages.
Cog - System Info Viewer Displays lots of useful hardware and network info
Chrome Apps & Extensions Developer Tool
Awesome Screenshot Screen capture for all or part of any web page. Add annotations, comments, blur sensitive info, and share with one-click uploads.
BuiltWith Technology Profiler returns all the technologies it can find on the page. BuiltWith’s goal is to help developers, researchers and designers find out what technologies pages are using which may help them to decide what technologies to implement themselves.
Giphy for Chrome Respond to emails, tweets and more with GIFs quickly and easily.
FireFTP FireFTP is a free, secure, cross-platform FTP/SFTP client for Mozilla Firefox which provides easy and intuitive access to FTP/SFTP servers.
FireSSH FireSSH is a free, cross-platform SSH terminal client for Mozilla Firefox and Google Chrome. Written entirely in Javascript!
Swap Proxy Swap Your Proxy Setting instantly just by a click.
NoScript Security Suite Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
Firebug development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page…
JavaScript Deobfuscator This add-on shows you what JavaScript code runs on a web page, even if it is obfuscated and generated on the fly. Simply open JavaScript Deobfuscator from the Web Developer menu and watch the scripts being compiled/executed.
PixelZoomer takes a screenshot of the current website and provides various tools for pixel analysis. You can zoom into websites (up to 3200%), measure distances and pick colors with an eye dropper. PixelZoomer requires Firefox 3.6 or higher.
Disable WebRTC WebRTC leaks your actual IP addresses from behind your VPN, by default.
Remote XUL Manager Manages the Remote XUL whitelist to allow websites and local files to load XUL content. For versions compatible with Firefox 41 and lower, see All Versions page below.
Selenium IDE is an integrated development environment for Selenium tests. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests.
ColorZilla Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies…
Random Agent Spoofer Rotates complete browser profiles ( from real browsers / devices ) at a user defined time interval. It includes many extra privacy enhancing options
DuckDuckGo Plus is the search engine that doesn’t track you. This add-on makes DuckDuckGo your default search engine and includes some other useful features.
ipFlood Simulate the use of a series of proxy changing at each new connection.
VimFx Short, Vim-style keyboard shortcuts for browsing and navigation, for a near mouseless experience.
User Agent Switcher The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
Flagfox Displays a country flag depicting the location of the current website’s server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more…
Greasemonkey Customize the way a web page displays or behaves, by using small bits of JavaScript.
Adblock Plus Blocks annoying video ads on YouTube, Facebook ads, banners and much more. Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
