There are several places where you can identify if a user account is validated or not. In the list view you can check the "User Access". For users who haven't verified, their status will be Invited. For the rest it ill be wither Verified or Allowed.
The user who hasn't been verified will be shown a alert marker in the email icon in the tiles view.
In our newly added Advisor section under Admin tab, we have a recommendation for unverified users. Here, you also resend the verification link for all the unconfirmed users.
Product Manager, Site24x7