There is an out of the box "Comments" Site Column in SharePoint. I can't figure out that whether it is of Plain Text type or of Rich Text type, as I need to have a Plain Text Multiple Line of Text field of "Comments" title in a Custom list and if an out of box solution exists, I would be able to use that directly.
The "Comments" site column from the "Core Document Columns" group of site columns is a plain text (not rich text) multi-line text field.