I like this idea and would personally find it really useful. I think having catalogs (or collections, if we’re thinking in a similar vein to Zotero) would actually complement MOCs.
I like to think of an MOC as the text version of my mindmaps. It’s a catalogue that has been consciously curated - by dividing items into categories, breaking down different aspects of a concept then linking notes etc. It’s a catalog but one that reflects your thinking process.
Having a ‘collection’ of notes in a given subject area / concept (either one that you plan to turn into an MOC, or one that spans several MOCs) would make it easier to make MOCs because you know where to look for notes and are less likely to have orphans. For example, knowing I need an MOC on ‘postcolonial state-building’ somewhere down the line, I could add notes to that collection. In another use case example, I might add notes to a collection ‘Feminist approaches to theory’ so I can pull notes from there when making an MOC on different approaches to theory in X discipline.
There’s probably a fair bit of overlap between this and feature requests for #multiple-word-tags or the various discussions on what to use tags for. That said, there are plenty of folks who use tags for action reminders/status indicators as well as concepts/ideas, so a collections feature would definitely help keep tag systems organised.
I also don’t know if this is at all possible, but being able to filter by collections as well as tags in Graph View would also be fantastic.