I'm currently doing some exploratory work on a new system. As the game progresses, a reasonably diligent player is fairly likely to acquire more characters than they're able to use at one time. So, I figure it makes sense to have some way to make use of the ones that aren't being used in the active battle party. My current idea is a system where characters can be sent on missions of some sort; they'd be made unavailable for a certain number of battles, after which they'd return with small but relevant rewards, such as money or crafting materials. This is super subject to change since at the moment I'm not even completely sure that what I want to do is programmable in RPG maker, but I do intend to have some kind of system even if this one specifically doesn't work out.