Despite my usual MO, I legit think that the Rookie-Level Digimon have some of the better designs in Digimon. Maybe this is just my love of Digimon World 4 talking, when my brothers, older cousin, and I beat the game as the starting 4 Rookies, but there's something about the Rookie-leveled mons that are just more appealing than their higher-level counterparts (not that they're not still cool, lol).

With all that said, Dorumon and Gabumon might be my favorite Digimon. Dorumon cause I got stuck playing as him in Digimon World 4 and I grew kind of attached. As for Gabumon, he was my favorite in the OG anime, whenever I could catch it.