Spring repositories with best-practice?

Question

Spring

On a new project, we decided to switch to Spring Boot and there are always questions about organizing code inside modules. To solve them, you have to turn to all kinds of guides and open-source repositories. Maybe there are some collections with projects that will be more substantial than any "spring-boot-example" with one service for recording an account from 3 fields in the database?
For myself, I have so far dug up only piggymetrics