The list below isn't meant to be exclusive, it's more so a collection of links that have helped me out along the way (and can hopefully help you). As you'll see, I've focused on Web Development such as: Ruby, Rails, Javascript. There is also a wealth of information on interview prep and applying to jobs.

With the list bellow, I hope I can help developers improve their skills and rise up in their career path.

Status: In progress

1. Start Here
2. Angular Best Practices
3. C best practices
4. C++ best practices
5. CSS Best Practices
6. Elixir Best Practices
7. Flutter best practices
8. GO Best Practices
9. HTML Best Practices
10. JavaScript Best Practices
11. Java Best Practices
12. Kotlin Best Practices
13. Laravel Best Practices
14. NodeJS Best Practices
15. SASS Best Practices
16. Scala Best Practices
17. Swift Best Practices
18. Objective-C Best Practices
19. PHP Best Practices
20. Python best practices
21. Ruby Best Practices
22. Rails Best Practices
23. ReactJS Best Practices
24. ReactNative Best Practices
25. R best practices
26. Rust Best Practices
27. TypeScript best practices
28. Vue best practices

• HTML Best Practices - @hail2u

• HTML5 (and Some CSS) Best Practice - Paulo Augusto Kunzel

• Frontend Guidelines - @bendc

• Google HTML Style Guide - @google

• Airbnb CSS / Sass Styleguide - @airbnb

• Dropbox (S)CSS Style Guide - @dropbox

• CSS Coding Standards and Best Practices - @stevekwan

• Google CSS Style Guide - @google

• Sass Coding Guidelines - @bigcommerce

• Sass-Guidlines - @blackfalcon

• Airbnb JavaScript Style Guide() - @airbnb

• es6-cheatsheet - @DrkSephy

• Common JavaScript "Gotchas" - @stevekwan

• Pragmatic Standards: JavaScript Coding Standards and Best Practices - @stevekwan

• JavaScript 规范 - @adamlu

• Google JavaScript Style Guide - @google

• JavaScript The Right Way - @braziljs

• MDN JavaScript guidelines - @mozilla

• W3C JavaScript best practices - @w3c

• Node.js Style Guide - @felixge

• RisingStack Node.js Style Guide() { - @RisingStack

• React Design Patterns and Best Practices - @MicheleBertoli

• React Style Guide - @coderjonny

• Advanced ReactJS Patterns - @kentcdodds

• React Interview Questions & Answers - @sudheerj

• Angularjs style guide - @mgechev

• Angular 2 Style Guide - @mgechev

• Angular.js: Advanced Design Patterns and Best Practices - @trochette

• React-Native Guide - @reactnativecn

• PHP: The Right Way - @codeguy

• PHP knowledge - @php-earth

• Style-Guides - @Integralist

• PHP Coding Standards - @maxdmyers

• Ruby Style Guide - @airbnb

• Ruby Tricks, Idiomatic Ruby, Refactorings and Best Practices - @franzejr

• Best Practice Patterns in Ruby - @avdi

• Ruby Best Practices, by Gregory Brown - @practicingruby

• The Ruby Style Guide - @bbatsov

• Shopify’s Ruby Style Guide

• Airbnb's Ruby Style Guide

• 53 Ruby on Rails Interview Questions and Answers

• Ruby Best Practices and Tips by Toptal Developers

• Ruby best practices beginners should know

• The Ultimate Guide to Ruby Timeouts - @ankane

• The Rails Style Guide - @bbatsov

• rails_best_practices - @flyerhzm

• The RSpec Style Guide - @reachlocal

• Rspec Best Practices - @abinoda

• Rails Database Best Practices - Christian Nelson

• Active Record Query Optimization Tips - Steven Li

• ActiveRecord: How to Speed Up Your SQL Queries - Stefan

• 53 Ruby on Rails Interview Questions and Answers

• Arel

• Production Rails - @ankane

• Securing Sensitive Data in Rails - @ankane

• Toptal's Ruby on Rails best practices

• Laravel: The Right Way - @laraveltherightway

• Laravel: The Right Way (Best Practices) - @uonick

• Swift Style Guide - @eure

• Design Patterns implemented in Swift 3.0 - @ochococo

• Swift Style Guide - @raywenderlich

• NYTimes Objective-C Style Guide - @NYTimes

• raywenderlich.com Objective-C style guide - @raywenderlich

• Style guide & coding conventions for Objective-C projects - @github

• Code Style & Best Practise for Objective-C - @wangshengjia

• Java Best Practices - @in28minutes

• Selenium-best-practices - @previousdeveloper

• raywenderlich.com Java Style Guide - @raywenderlich

• Java Best Practices Guide

• 30 Java Programming Tips and Best Practices for Beginners

• Best practices in kotlin - @JackyAndroid

• kotlin-style-guide - @yole

• raywenderlich.com Kotlin Style Guide (in progress) - @raywenderlich

• Uber Go Style Guide - @uber-go

• Go Best Practices - @mehrdadrad

• Go Style Guide - @AgtLucas

• Golang tutorial series

• Golang cheat sheet by golang-dojo

• Soham Kamani - Golang

• Rust Style Guide - @ubsan

• The Elixir Style Guide - @christopheradams

• Elixir Style Guide - @lexmag

• Credo's Elixir Style Guide - @rrrene

• 10 Killer Elixir Tips #1

• 10 Killer Elixir Tips #2

• 10 Killer Elixir Tips #3

• Elixir cheatsheet

• Elixir metaprogramming

• Scala Best Practices - @alexandru

• Databricks Scala Guide - @databricks

• TypeScript Best Practices - @BestCoderDotInfo

• Performance best practices
• Flutter: Best Practices and Tips - Kinjal Dhamat
• Flutter Development Best Practices - Derrick Mwiti

• Tips & Best Practices
• 10 Good Practices for Building and Maintaining Large Vue.js Projects
• 12 VueJS Best Practices for Pro Developers

• C Programming Best Practices – Must know to become an Expert
• c-style - @mcinglis

• Python Best Practices – The only guide to become Python Expert
• The Best of the Best Practices (BOBP) Guide for Python - @sloria
• Python Best Practices and Tips by Toptal Developers
• Code Style
• 11 Tips And Tricks To Write Better Python Code
• Python tutorial: Best practices and common mistakes to avoid

• 3 Coding Best Practices for C++
• Collaborative Collection of C++ Best Practices - @lefticus
• The C++ Core Guidelines - @isocpp
• C++ Best Practices
• C++ Best Practices - @puppetlabs
• Modern C++ best practices for exceptions and error handling - microsoft
• Top Ten Tips for Correct C++ Coding

• Beyond Basic R - Introduction and Best Practices
• R Code – Best practices
• Best Practices for Writing R Code - @swcarpentry
• R CODING STYLE BEST PRACTICES
• Good Practices in R Programming

Contributions are always welcome! Please read the contribution guidelines first.