My favorite one is my ring finger because I like to put a ring on it, currently it's a ring with a little amethyst stone.
The second is my pinky, because I always ask my IRL people to pinky promise whenever they promise me things. It's a habit now.
Thinking about it now, if I had to pick favourite fingers, it’d be my middle and ring fingers my middle finger because I use it a lot when typing, and my ring finger because of the rings I wear on it, especially this promise ring someone gave me years ago…