How to get items(my custom class) by a custom id I paired them to?

I got a list of ids(strings) in my save file. And I got many items prefabs(each has unique id). I wanna get an item corresponding to its id.

I was thinkin of addin a dictionary to my gameManager(singleton) with ids(Strings) and items corresponding to it but it will be pretty fat…Is there any better way?

I used a list with ids…But any answers will still be apreciated