For starters I would recommend, looking at system design primer and Hello Interview. If you want to read more in detail consider getting the Designing data-intensive applications book.
Here are some popular system design interview questions:
- ChatGPT
- Web Crawler
- TinyURL
- Youtube
- Google docs
- Facebook Newsfeed
- Uber
- Job Scheduler
- Robinhood
- Elevator
- Key Value Store
Make sure to have a system design framework that you follow regardless of the question
- Ask clarifying questions
- Requirements (Functional and Non-Functional)
- Storage and Bandwidth Estimates
- APIs
- Data Model
- Architecture Diagram
- Discuss Pros and Cons of approaches
- Failure Cases
Practise using tools like Excalidraw.