A great youtube channel with fantastic tutorials and topics for beginners in robotics.
James BrutonThis is a great channel if you just want to chill while watching how interesting concepts come to life. James has worked on robots for many years and his experience and knowledge to bring a project together really shines through!
Digital Signals TheoryAn ebook in website form created by Brian Mcfee. The site covers many topics of digital signal theory and has very easy to follow examples and explanations for signal theory.
Massively online open courses, Helsinki university has a fantastic platform which contains their university courses, free of charge and open for anyone. You can even obtain credits for completed courses and alot of them are rolling admission.
FullStackOpenAnother course by Helsinki university, focusing on fullstack web development with react, nodejs, mongodb along with other great modern technologies to take your stack to the next level
LearnCPP.comA free website teaching modern C++. If you are interested in low level programming and want to understand what your computer actually does under the hood when programming then understading the basics of a low level language such as C or C++ is extremely important.
If you are interested in the inner workings of statics and materials when under load and in stress then this channel is an amazing resource with incredible animations to help visualize the inner workings of materials and loads. All of the contents are crucial for mechanical engineers to understand and have skills to implement.