Here are three plain text emails for people already subscribing to an email list.
The left hand side shows the email preview before opening including the sender, a subject line, and a snippet. This is an additional line of text that can get you to open an email. Many don't even know about this extra feature.
The three companies are the following: (1) Johnson & Johnson; (2) A-1 Performance Motor Oil (fictional company); and (3) Macy's.