How to search for system-generated accounts through an Account saved search? I tried to look at the System Notes but I noticed that the not all of them do not have the "Create" type.

System-generated accounts don’t have a number assigned to them. If you’ve already assigned a number to them, that change should be captured in the system notes. Have you tried a saved search tracking changes to the account?

There is a Help article called "Feature-Specific, System-Generated Accounts" that lists out all of the available system-generated accounts available.