A reminder and a request.
The reminder is for anyone interested in category theory at an introductory level — whether giving a course, or taking a course. There is a page here of links to online notes and freely available articles and books and even videos. Some have found my own work-in-progress Category Theory: A Gentle Introduction helpful as it is particularly aimed at beginners (note however that this is pretty rough and ready in parts, and very far from finished even as a first draft — but I’m currently distracted by another project!).
And the request? Please do let me know about any useful new additions that could be made to that page of links.