You have some GKE standard clusters that you want deleted. What should you do?
Possible Solution #1 (from the Cloud Shell or with a gcloud command)
1. Delete the instance group of the instance for the cluster you want to delete. To do this in the web UI, go to Compute Engine -> Instance Groups. Check the box on the left-hand side and click on "Delete".
2. Go to the ">_" icon in the upper right-hand corner. When you hover over it, it should say "Activate Cloud Shell". Click on it.
3. Run this command (but replace "gke-standard-cluster-1-default-pool-abcd1234-56ef" with the name of the instance and replace "us-central1-a" with its regional name):
gcloud compute instances delete gke-standard-cluster-1-default-pool-abcd1234-56ef --zone us-central1-a
4. Respond with a "Y" to the next prompt.
Possible Solution #2 (from the console or web UI)
1. Go here: https://console.cloud.google.com/kubernetes/list
2. Click on the cluster you want to delete.
3. Click the "Delete" button.