StepMania is a free and open source, cross-platform rhythm game. It supports common key-based rhythm game formats (including 4-panel and 5-panel dance games among others), as well as keyboard and dance pad controllers.
It is customizable with user-made add-ons such as themes, and provides an integrated editor for creating your own simfiles.

Stepmania by default only comes with three songs, so you are expected to add your own content! There are multiple websites out there for hosting songpacks, here is one of them: https://search.stepmaniaonline.net/

To run: Menu -> Games -> Stepmania
To run in a terminal: /usr/local/stepmania-5.1/stepmania

How to customize stepmania (adding songpacks, theming, etc):
https://github.com/stepmania/stepmania/wiki/Customization

Your User Data folder is where you place custom content (like songpacks):
~/.stepmania-5.1