If you are new to Power BI or just looking where you can keep up to date with the technology, the following links are a great place to start. (Updated March 2021)
Criteo has released a real world sample data set of over 1TB and provides over 4 billion examples with binary labels (click vs. no-click) including over 156 billion total (dense) feature-values and over 800 million unique attribute values
The Kimball methodology is the go to process for architecting your BI process. This book is the latest version and covers a great deal of what you need to know.