As it seems there is a package manager for everything these days, I have created this page as a place to document all the different ones I find in my travels.
A package manager or package-management system is a collection of software tools that automates the process of installing, upgrading, configuring, and removing computer programs for a computer’s operating system in a consistent manner.
Wikipedia

npm
JavaScript
npm is the defacto-standard package manager for JavaScript. It has contains a wide variety of JavaScript packages and is supported by npm, inc.

Yarn
JavaScript
Yarn is an alternative package manager for those who worry about some of the previous reliability issues that npm faced. It allows you to use and share (e.g. JavaScript) code with other developers from around the world. Yarn does this quickly, securely, and reliably so you don’t ever have to worry.

Composer
PHP
Composer is a tool for dependency management in PHP. It allows you to declare the libraries your project depends on and it will manage (install/update) them for you.

Helm
Kubernetes
Helm helps you manage Kubernetes applications — Helm Charts help you define, install, and upgrade even the most complex Kubernetes application.