If you're using GitLab to manage your software delivery, you should also look at GitLab CI/CD for your continuous integration and continuous delivery needs. We've found it especially useful when used with on-premise GitLab and self-hosted runners, as this combination gets around authorization headaches often caused by using a cloud-based solution. Self-hosted runners can be fully configured for your purposes with the right OS and dependencies installed, and as a result pipelines can run much faster than using a cloud-provisioned runner that needs to be configured each time.
Apart from the basic build, test and deploy pipeline, GitLab's product supports Services, Auto Devops and ChatOps among other advanced features. Services are useful in running Docker services such as Postgres or Testcontainer linked to a job for integration and end-to-end testing. Auto Devops creates pipelines with zero configuration which is very useful for teams that are new to continuous delivery or for organizations with many repositories that would otherwise need to create many pipelines manually.