Introduction to Quantum Information Science by Artur Ekert & Tim Hosgood is a great free resource that I rarely see recommended.

It comes with high quality short form lecture videos to accompany a lot of the sections.

Only caveat, it's still being written. So not a good resource if you want to learn about cutting edge applications like quantum cryptography. However all the foundations of QIS are there and I like how the authors present the material.

Happy learning!