MelonLoader is a free-to-use utility that allows you to load any mod for any app developed using the Unity engine. It is a freeware general application that's modern.
Here are some screenshots to illustrate the features and user interface of this application:
Universal mod loader for Unity games. Screenshot of MelonLoader - 1202px · 1102pxMelonLoader: Unity Engine. Screenshot of MelonLoader - 1202px · 1102pxOwn set of modifications. Screenshot of MelonLoader - 1202px · 1102px