Our friend, Fallen Angel Olivia, has created another plugin again called Meta Controls! 
This is a RPG Maker MV plugin that lets you control switches and variables that last across a meta level on a game. A switch or variable designated to function as a meta switch or meta variable can persist across different save files. To assist in controlling meta properties of the game some more, the developer can assign common events to run at the start of a new game or when a game is loaded. Saving the game can also register map data to variables.