My question is regarding to thee kuberetes architeture eitself. I'm currently working with Kubernetes within the Google Kubernetes Engine. I noticed that Google clusters have something called Pool, although It doesn't seem to be a Pool concept on Kubernetes docs. Is it exclusive to Google Kubernetes Engine?
The Node Pool resource that you are (I'm assuming) referring to is part of the Kubernetes Engine API -- not to be confused with the actual Kubernetes API. Despite the similar name, Kubernetes and the Kubernetes Engine are different products: The latter is a product for managing Kubernetes clusters and part of the Google Cloud platform, separate from the Kubernetes projects itself and adding its own APIs on top of Kubernetes (like, for example, for managing Node Pools).
For reference, the Kubernetes API reference offers a complete list of all resources that are provided by the Kubernetes API itself (which does provide Nodes, but not NodePools).