Yanfly Engine Plugins is a plugin library made for RPG Maker MV, a wonderful piece of software to help you make that role playing game of your dreams. You can find out more about RPG Maker MV here.
You can grab the plugin here:
English Link
RPG Maker MV comes with Self Switch functionality. However, the number of Self Switches provided is a mere 4 in total, not enough for some of the more complex events. This plugin will let you extend the number of Self Switches. Self Variables, on the other hand, do not exist in RPG Maker MV, so this plugin will provide functionality for that as well.