Node.js makes it easy to build dynamic web pages and services on the backend with javascript, using the very well-optimized V8 JIT compiler and a non-blocking IO model.

Typescript is a superset of Javascript that adds type information. Explicitly typed data makes collaborating and dealing with complexity easier by ensuring most bugs are found at build time instead of during QA.

Python's elegant syntax is super expressive and easy to read. It's a great language to learn on, to prototype with, and to rapidly build sophisticated, maintainable tools and applications.

Rust is a modern multi-purpose programming language with a unique mix of high level abstraction and low level control. It uses a memory ownership model that allows the compiler to guarantee safe concurrent memory access without an associated runtime cost. It's tricky to learn, but powerful; capable of generating extremely CPU and memory efficient binaries.

AWS's tooling for cloud infrastructure is extensive and powerful, enabling small teams to create and deploy highly available systems quickly. Defining infrastructure through code with CloudFormation makes devops automation a breeze.

Linux is exemplary on many fronts. It competes with the best proprietary OS's while maintaining end-user freedom and control, with no up front cost. It has been a boon not only for software freedom generally, but for enterprise computing, hardware vendors, education, and more.

Git is another open source gem that deserves its ubiquity. Killer features include high speed, a quality diff algorithm, integration with SSH, dead simple setup on *nix systems, and a variety of great (but optional) web interfaces and GUI tools.