Partime:
I am an avid saver/collector of contemporary covers, especially those that match my topical collections. Below are three that I show as examples.
1. First is a great find of a contemporary cover fitting into my Aircraft on Stamps & Covers collection. It is a non-philatelic commercial cover from an appropriate business franked with a contemporary definitive stamp that has a fantastic reproduction of a Bristol F.2B WW I fighter in RAF colors.

2. Here is another Aircraft on Cover that I got in the mail in 2014. It is a solicitation for money from the Commemorative Air Force
with a photo of a Curtiss Model 84 Helldiver.

3. This is another solicitation for money from the Gettysburg Foundation. It would fall into the Junk Mail category, but I save these fully illustrated covers because I see them as contemporary examples of 19th- and early 20th-century advertising covers.

Don