Is there any fruit or vegetable that doesn't have its own special tool? (In case you were wondering, that's a rhetorical question.)
Peppers have the Progressive Pepper Corer Duo ($9.69), which is actually a set of two tools, paired to core and seed peppers of all shapes and sizes. The larger corer works on bell peppers and the like, while the smaller handles jalapeños, serranos, and other diminutive varieties.
I have to admit that most of the time, I simply cut peppers in half and remove the core and seeds with a knife—because usually my next step is cutting the peppers into even smaller pieces. But there are occasions when it's desirable to leave the pepper whole, like when stuffed peppers are on the menu.
I gave the bell pepper corer a side-by-side test. Well, technically speaking, it was a one-after-the-other test—where I cored peppers with a knife and with the corer. Of course, I was able to core the pepper with the knife, but the corer was a heck of a lot faster, since you just stab, twist, and remove the core. The peppers needed to be rinsed to remove loose seeds, but it was just a few seconds of work for each pepper.
The same concept works for the smaller corer, but on a smaller scale. And, the big bonus for me, as a contact lens wearer, is that using the corer minimizes right-hand contact with hot peppers, keeping my fingers a safe distance from the pepper's interior.
The only problem I had with the jalapeño corer was with one radically bent pepper, but those with a gentle curve were fine. And I'm sure that trying to core that bent pepper with a knife would have been just as problematic.
While these are specifically marketed for use with peppers, there's no reason you couldn't use them for cutting holes in other fruits and vegetables, like tomatoes, melons, or banana cupcakes. (Wait ... banana cupcakes aren't a fruit?)
Since the corers are made from plastic, they'd be safer for kids to use, and great for adults who have knife-handling issues. They're dishwasher safe and nest together for storage.
While these aren't an essential kitchen item, they do make coring peppers a lot easier, so if stuffed peppers are often on the menu often or in large quantities, these could be handy to have. And then once you have them, you can start coring holes in your carrot muffins, too.
Disclaimer: Testing samples were provided to Serious Eats.