What are the common factors / design pattern of the open source React UI libraries? [closed]

Question 1: What are the common factors / design pattern of the open source React UI libraries e.g. Material UI, Ant Design and React Bootstrap?

I would like to create my own React UI library for business use without using external UI libraries. Thus, I want to know what I could learn from the existing popular UI libraries and apply to my own.

Currently, I have limited use cases for each component. What I would like to achieve is creating those components with the existing confirmed use cases and add those possible use cases in future.

Question 2: So... how do those open source React UI libraries mentioned above manage their current and future use cases?