How to call (variables) mini-games that are in the general program (collection of games)?

Question

C++ / C#

I'm working on an app (a Unity game, so I'm using C# ) .
Inside the application are other "little games". I wonder how to separate games within a common application.
The logic is general (I use interfacs and implement it for each game), but with the name of the variable where you need to specify a specific game, I don’t know how to call it better.
Example: you need to choose which game to run (let's say the GameController needs to know what games it has, but how to separate games from each other and find that one and how to access it (variable name / in an array) to be called).
I considered listing games by index (and having a game description file - index in the README) but didn't find it a very good option.
Please tell me the best (correct) way to separate the entities of the games inside the application. Thanks in advance