Besides the previous posts' main, impactful tutorials, I came across some nice material in slightly more hidden/unknown places. There are authors that deserve more attention, because their content is high quality, and even more importantly, teach the foundations of fresh developments.
A. The .NET stack
For me, Entity Framework was something that I wanted to learn this year. But all that I found were books and tutorials - mostly complicated and obscure, that I continuously gave up.
Until I found this simple but excellent material for EF Core, that laid down the foundation for me:
The Razor Pages tutorial in ASP.NET Core, a simple, yet beautiful one, which made me studying this further:
Fireship. I am amazed a little bit how posts in dev.to do not really mention this site as an excellent resource:
In my opinion, Firebase is a very interesting solution, and for web developers, a must to dive into. I wish I could have more time to study the material on Jeff's site above, but now I am caught in the .NET world with my current project.
Angular Material tutorial. This design system seems very modern and powerful, yet the knowledge requested is advanced, and the best tutorial overall which was not too basic: https://code-maze.com/angular-material-series/
PWA with Angular. Unfortunately I did not finish this, but I very much liked it as it combines Angular, Material Design, Firebase and PWA: https://www.pwawithangular.com/