If you have already mastered the fundamentals of SCOM and are eager to take your skills to the next level by learning how to build Management Packs from scratch, Microsoft has an excellent resource for you. They have published a series of informative videos that will guide you through the process of developing and honing your Management Pack authoring skills.
Check out the video series here: https://learn.microsoft.com/en-us/shows/system-center-2012-r2-operations-manager-management-packs/
These videos provide valuable insights and step-by-step instructions, making it easier for you to create custom Management Packs tailored to your organization's specific monitoring needs. Whether you're a seasoned SCOM user or just getting started with Management Pack development, this resource will empower you to enhance your monitoring capabilities and achieve optimal performance in your IT environment. Happy learning!