I am going to name one other than the obvious Albion Arc and Katalina's innermost teachings.

I really liked Yggradsill Malice in Erste Empire arc followed by Rosetta's reveal as the Rose Queen to the crew and staying back to hold the fort, let alone for Yggdrassil. It was all super high tension with emotions running very high at that time. I also liked Drydoit Belt with Kikuri, where Katalina and Rackam I think lost their memories briefly because of the primal beast. Such were simpler times in the main story quest :).