Starduster mini-comics - 1985

Three issues of this comic were packaged in boxes of G.I. Joe Action Stars cereal, and are dated 1985. They promoted Hasbro's Starduster action figure mail-in offer, and were part of a larger three-part story.

You can find scans of the comic (1, 2, 3) at YoJoe.com, as well as a page dedicated to the Starduster action figure.
 

Super Trooper mail-in offer - 1988

"Operation Single-Handed"

This short comic story doubled as an order form for one of Hasbro's mail-in offers, the Super Trooper action figure. The insert was packaged with action figures sold in 1988. The story introduces the Super Trooper character.

Scans of the insert can be found at YoJoe.com, as well as a page dedicated to the Super Trooper action figure.
 

1993 mini-comics

These small comic books were packaged with G.I. Joe action figures released in 1993. These stories were co-written by Larry Hama, and though they aren't really a part of the Marvel continuity, they don't specifically contradict it. The artwork was done by Marvel Comics artists, including Andrew Wildman, who had a long stint on the monthly series.

Summaries and reviews
 

G.I. JOE vs Cobra mini-comics - 2002

This series of comic stories was packaged with G.I. Joe figures released throughout 2002. The stories were written by former Marvel series writer Larry Hama, but were set firmly in the toy storyline and not the other comics.

Artwork from these comics can be found here at YoJoe.com.

G.I. JOE: Valor vs Venom - 2003/2004

"Dawn of the V-Troops"

This comic book was included with the G.I. Joe catalogs packaged with toys starting in 2003. Though its dated 2004, it first started towards the end of the previous year. Like the previous comics, it was written by Larry Hama and it sets up the toy's storyline at the time, "Valor vs. Venom".