Summary: Instructions on how to check what apps have authorized access to your Google account, and how to revoke access if necessary.
It is considered a best practice to routinely check what apps have access to your Google account, and apps you no longer use, should have their access revoked. To check what apps have access to your Google account, follow these steps...
Once logged in, visit https://myaccount.google.com/
You will be presented with a list of apps you have granted permission to access to your Google account. Scan the list to look for any apps you do not want to have access, no longer use, or may have been mistakenly authorized.
Click on an app to see more information about the access it has, and when it was authorized. To revoke access, click the REMOVE button. The app no longer has access to your Google account.
Repeat for any apps for which you wish to revoke access.
For more information, see Google's Account Help document on apps connected to your account...