Connected apps are programs and games that you can sign in with your Google account. This way you don't have to remember your username and password in applications.
You can view the full list of such applications on your phone at Settings> Google> Connected Applications.
The selected Google account is shown at the top of the screen. You can change and log in from another account.
As you can see in the screenshot, I have several such applications. and I go to each one through my Google account. If you do not trust a program or want to remove it from your phone, you can disable the use of your Google account to log in. Just select the application you want and click “Disable”.
At the same time, see what permissions this program has. For example, Clash Royale has access to Google Play games.