What you are looking for are programs that create text files when you drag them to Finder or File Explorer, as that is the kind of drop Scrivener is looking for in the binder, corkboard and outliner views.
You’ll probably just need to download demos and experiment to figure that out, as this isn’t typically the kind of feature people boast and preen about on their websites. It’s just something a developer may do or not do, and may not even document it if they do.
With some programs it would be of dubious utility, since they work directly with files already, like Obsidian. Programs like that can often work well with Scrivener’s folder sync feature. Why drag and drop and import and export and all that, when you can just load your project or press a sync button and have any new notes made in that program natively, imported, and all content edited in older notes, updated?
So if I was looking for a “better scratch pad” or a front tool for Scrivener that integrated well with it, that’s the direction I would be looking!