The Veggie People are the inhabitants of Veggie Village who first appear in "The Jiggler." They appear to be normal fruits and vegetables. The only named Veggie Person is Stanley, a watermelon. Some unnamed Veggie People include a squash, a pumpkin, some carrots, and a few heads of cabbage.
The Science Conference takes place at Stanley's house, suggesting it is important to the Veggie People. At the Science Conference, the Veggie People have some scientific-looking equipment, though how they made or brought it there is unknown (let alone how they got there in the first place). Princess Bubblegum seems to acknowledge their unresponsiveness but not think anything unusual of it.
Not all of the Veggie People are vegetables (as in the food), so they might be named after the medical ailment of being a vegetable, which is someone who cannot move. This would be appropriate because none of the Veggie People react to Princess Bubblegum in any way.