Front End Name List/Search Gives DB Error
Looks like you don't have summary_overlay profile in your civicrm_uf_group table. This is a reserved profile which we cannot delete or disable from UI.

So its possible if the name is edited or the profile is deleted from your db due to some reason. To check-


Open civicrm_uf_group table.
Check for the entry for Summary Overlay profile. This is with id 7 on demo site of civicrm.
If you don't find this profile -  error is due to this reason.
If you find it - check the name column of this profile and change if it is anything other than summary_overlay.