The Comic-Stripped American (Book, Arthur Asa Berger, 1973)

You can borrow it digitally here.

Snoopy and "It Was a Dark and Stormy Night" (Book, Charles M. Schulz, 1971)

The creation, and complete unexpurgated text, of the Great American Novellaellaella, with book-within-the-book cover art by one Lucille van Pelt. You can digitally borrow it here. You can read an article about it here.

The Cathy Animated Specials & McDonalds Ads (Videos, 1987/1988/1989/1998)

Based on the classic newspaper comic. So many links to post! ACK!

Cathy (1987)

Cathy's Last Resort (1988)

Cathy's Valentine (1989)

McDonald's salad ads: this one, this one and the one with Mike Ditka (1989)

JCPenney ad (1998)

See also these podcast episodes about the specials, episodes 2, 5 & 35 of A Special Presentation, or, Alf Will Not Be Seen Tonight, co-created by @thehungryreader and @bitterkarella.

The Essential Guide to World Comics (Book, Tim Pitcher & Brad Brooks, 2005)

You can digitally borrow it here.

Note: that isn't an off-model Nancy in the upper left - see the key diagram on one of the first few pages (viewable even without borrowing).

Ziggy Christmas Card (Apple II, 1986)

A square, magnetized Christmas card with a hole in the middle, otherwise known as a 5 1/4 inch floppy disk. You can play it in your browser here. Ziggy Zigsmas!

Popeye Meets the Man Who Hated Laughter (Video, Jack Zander, 1972)

The massive crossover wherein comedy newspaper comic characters need rescuing by adventure newspaper comic characters. You can watch it here.

B.C. Monroe Shocks and Struts Ads (Videos, ~1988/1989)

Two auto part ads starring characters from the newspaper comic strip; you can watch them here.