I'm thinking adding options something like:

"Include non-active cards in visual spoiler: [ ] No [ ] Yes, with 'inactive' marking [ ] Yes, unmarked"

"On cardlist: Show non-active cards [ ]"

The "marking" will be a big bar across the top half of a card's art box saying "INACTIVE".

I'm not sure exactly what, but I think something like this would be quite useful. (Perhaps different views for "uncategorised cards" "active cards" "all" or something?)

Not quite sure what you mean by "uncategorised"? My databse does support letting "Active" be a three-value logical - true, false or null - so I could provide that option. But that's not what I'd been planning here.

What kind of views have you wanted that aren't available?

Sorry, I'm not quite sure, which was why it was very vague; I think "uncategorised" basically meant "inactive" but with a different connotation. The point being, when you start to design, you're likely to have a bunch of designs with no rarities, card codes, etc assigned yet, and at that point you want the default views to show those cards, and then later you want the default views to show only active cards, typically now assigned a code. The existing interface probably does support this more-or-less, but I'm not exactly sure because I haven't looked properly.

I should also provide the ability to mass-assign active status of true or false. noyahuid encountered this here.