Elite trainer box comes to mind for me, that’s how I ship bulk
Oops, just as I delete the post (because I think I figured out how to do it), I got a response haha. And I don’t have any Elite Trainer boxes – but I ended up doing this:
The cards are very compact so I’m worried about the different curvatures damaging the cards, but I’m just going to cross my fingers that this works…
Anyway, mods can delete this thread if they’d like to.