When there's a bunch of cast and more specifically crew appearances, I have to either do each episode individually or bulk add them and do one at a time. It'd save a lot of time and clicks if it was possible to be able to select all the needed cast or crew in bulk add and then click the episodes once instead of having to do one person at a time and clicking each episode.
Bulk guest crew would also be helpful, it might not be used as much, but for British shows for example usually have the same writers or directors for all or most of the episodes. Gavin and Stacy comes to mind in particular where all 21 episodes were written and directed by the same people.