In the future you could clone existing or create new apps yourself, and share them with other users, so you have the control of all the apps. But (I think) you can’t prevent other users that are part of your account from creating new apps or cloning apps without you knowing it.
It would be nice to have a dashboard that gives you the big picture of your account, including apps that you don’t know they exist. Perhaps having a dashboard like the one described in this old FR , but with some additional details for multi-user accounts, would have helped you.