Here are some references for Category Theory.

• https://ocw.mit.edu/courses/mathematics/18-s097-applied-category-theory-january-iap-2019/lecture-videos-and-readings/index.htm
• https://www.youtube.com/watch?v=UusLtx9fIjs&t=525s&index=2&list=PLhgq-BqyZ7i5lOqOqqRiS0U5SwTmPpHQ5

Spivak and Fong also released a .pdf on Category Theory that is interesting, dense, and beautifully diagrammed.