The below blog is a walk through of removing an unwanted plugin from vCenter this may because the application or virtual machine has been deleted and has left the plugin in vCenter.
Take a backup of vCenter first (offline snapshot or sftp backup)
First find the unwanted plugin in your vCenter plugin area. Click the three line > Click Administration > Under solutions click client plugins
Sign into your vcenter via the browser
Use your sso administrator@vsphere.local account and sign in
Click content
Click ExtensionManager
Click more > find your plugin in the list
Copy the key > highlighted below
Click UnregisterExtension
Paste the key and click Invoke Method
Confirm it has been removed from the list
You will need to restart the vCenter UI for the changes to reflect in vCenter plugin area
If the changes don’t reflect still, reboot the vCenter from cli or UI
Repeat the process for the other vCenters that have this plugin
Plugin is now gone
