Here are some of the gems of websites for every Frontend Developer Should Know

1. Stack Overflow - a platform for asking and answering coding questions.

2. GitHub - platform for version control and collaboration on coding projects.

3. Node.js - the official website for Node.js, a popular open-source platform for building server-side applications.

4. Django - the official website for Django, a high-level Python web framework.

5. Ruby on Rails - the official website for Ruby on Rails, a web application framework written in Ruby.

6. Laravel - the official website for Laravel, a PHP web application framework.

7. PostgreSQL - the official website for PostgreSQL, an open-source relational database management system.

8. MongoDB - the official website for MongoDB, a NoSQL document-oriented database.

9. AWS Documentation - the official website for Amazon Web Services (AWS), a cloud computing platform.

10. Heroku - a cloud platform that makes it easy to build, run, and manage apps.