Although Ponchomon has appeared a few times in the Digimon universe, hardly any official merchandise of him exists.
The Adventurers' Battle Program
The program for The Adventurers' Battle shows Ponchomon along with the other Digimon who appear in in the movie. The description under Ponchomon's picture describes him as, roughly, "a unique cactus-like Digimon with maracas in his hat."
The Adventurers' Battle Film Comic
Ponchomon also appeared briefly in this comic comprised of stills from the movie. Thanks to Fandramon for this image.
Manga: Digimon Next
Ponchomon's Battle & Evolution card BO-388 was featured on a Japanese poster advertising the card series. Ponchomon and one of his US Digibattle cards also appeared on mini posters included with some US Digimon merchandise.
I commissioned this amazing custom Ponchomon figure from Digimon Prototyping! The quality, detail, and color of the figure are just fantastic, and I'm delighted to finally have a substantial piece of merchandise of this wacky cactus.
I created my own Ponchomon plush based on the pattern I worked out for my Togemon plush. One good cactus deserves another!