As of Vanilla v5.3.0, the following animations are predefined:
Supported classes = 'fade-in' | 'fade-in-left' | 'fade-in-right' | 'fade-in-top' | 'fade-in-bottom'. Additional classes can be used but they must be predefined in one of the Less files.

The above comes from Vanilla's example.json. It's worth reviewing because it lists other predefined classes that can be helpful.