Pick a checklist you wants to learn.
MarkDown
Markdown is a popular lightweight markup language used for formatting plain text documents. It is widely used by developers, writers, bloggers, and anyone who needs to create and format text documents quickly and easily.
SASS
Sass is widely used by web developers and designers, and it's supported by many popular web development frameworks and platforms, including Bootstrap, Foundation, and WordPress.
MySQL
MySQL has been downloaded more than 140 million times and has over 17,000 customers in more than 100 countries, according to the official MySQL website.
Dart
The programming language is designed for client development such as for the web and mobile apps, and it can also be used to build server and desktop applications.