Resources

CFD-online. Largest forum where you can find all from discussions to job listings.
Scicomp-stack-exchange. A community Q-A site where experts answer your questions (and you get to answer a few!).
Dr. Wolfgang Bangerth's video lectures. A scientific computing course based on Deal.II library.
Prof. Nick Trefethen's NYU Lectures on Approximation Theory and Approximation Practice.
Scientific Computing for DPhil Students by Prof. Nick Trefethen.
Numerical Linear Algebra and Element-Based Galerkin Methods by Prof. Frank Giraldo, NPS.
The missing semester of your CS education: MIT course on tools such as command line, Git, text editors, scripting etc.

Awesome Lists about all kind of interesting topics. Check out the awesome-math section.
TikZ tutorial.
Git (version control system) tutorial.
A hello-world tutorial to CMake.
Lectures in Turbulence for 21st Century.
An Introduction to the Conjugate Gradient Method without the Agonizing Pain. An excellent tutorial.
Templates for the Solution of Linear Systems: Building Blocks for Iterative Methods.
Mathematics, Numerics, Derivations and OpenFOAM A free ebook.
NASA Tutorial on CFD Verification and Validation
Must-read papers on Physics Informed Neural Networks (PINNS). Also contains a list of useful softwares.

3Blue1Brown Probably the best linear algebra course you can find online. Highly recommended!
Welch Labs Check out 'imaginary numbers are real’.
AMATH301, Nathan Kutz, Data4Bio, Steve Brunton: Youtube channels exploring topics in numerical analysis and data sciences. Very useful tools for a computational/data scientist.
StatQuest: Simple intuitive explaination of topics in machine learning and statistics. Watch out for the 'BAM!’ moments!
Luis Serrano: Machine learning and math made easy.

Sabastian Lague on coding adventures.
Kurzgesagt- In a nutshell. A very informative YouTube channel about science, history and technology. Animations are beautiful.
Tech Ingredients A very cool channel on engineering.
Applied Science A very cool channel on science.
ColdFusion. A YouTube channel about contemporary topics in science and technology. Very informative and entertaining.
CGP-Grey. Topics cover a mix of geopolitical analysis, history and technology.
Veritasium. Another great channel exploring science.
Smarter every day. One question at a time!
Curious Droid 'Caspian report’ equivalent of science, technology and discovery.
Caspian Report 'Curious Droid’ equivalent of geopolitical analysis.

WaitButWhy A very important blog everyone should read. Particularly the Elon Musk series, a series on procrastination, and The AI revolution.

Acapella Science Very talented artist / scientist making acapella science songs.

Primitive technology. An amazing YouTube channel about primitive technology. Not a single modern tool used!

Medlife Crisis: Dr. Rohin Francis is a medical researcher and a cardiologist with a great sense of humour.

OpenFOAM, open source CFD toolbox.
SU2, open source CFD and optimization code.
Deal.II, open source finite element library.
FEniCS, open source platform for solving PDEs using FE methods.
Salome-platform, open source integration platform for numerical simulation. Includes pre-processing tools.
Gmsh, free three dimensional finite element mesh generator.
Triangle, a two-dim mesh generator and Delauney triangulator.
Paraview, post-processing tool for large data.
Mayavi, post-processing tool with python scripting capabilities.
Nektar spectral / hp element framework.
ParMooN Parallel Mathematics and Object Oriented Numerics.