HTML & CSS
HTML and CSS in combination with bootstrap. I have also experimented with creating wordpress templates.

JavaScript
JavaScript with AngularJS, as well as Jasmine, Mocha-Chai testing frameworks.

PHP
Using php to connect HTML / CSS / JavaScript front-ends to a MySQL back-end.

Python
Python and its myriad of libraries to create cmd-line applications.

Java
Using Java on the Android platform to create applications and games.

C#
Using C# to create console applications, and WinForms to create applications and a puzzle game.

MYSQL
Using MySQL as a DBMS, covering complex queries, security and database design.

Cloud Computing
Using AWS or Azure to host servers for applications/ websites.

Art Design
Using Adobe software: Lightroom, Photoshop, Illustrator etc. to create outcomes

Version Control
Using GIT to work on a project collaboratively