Is there a way to search documents by approver?

Approval document

In My Documents or Manage Documents, click on the Manage Columns icon, and select the “Approvals?” data property. The user can pin the column and export the list.

To filter documents by approvals in My Documents or Manage Documents, use the Universal Side Tray (UST) and select the Filter icon. Then, choose "Approvals" as Yes, and the left-hand response view will display all documents with approval status as Yes. You can name and save this view for future use, and even create multiple filters like a toolbelt.

For pending approvals, the preferred method would be the system report or report module and access the Document Approval Report. This report will show all documents with a Pending Approval status.