From my experience, these are how I would rate the plants that come from the dirt and into our fridge. Remember this is my opinion, so it is automatically better than yours, but you can tell me your grievances in the comment section anyways.
Carrot: 2 Stars: Ah, the classic carrot. It's not really impressive in its own merit when you're looking to increase stats, but it's abundant in the world. You're able to instantly get carrot seeds by plucking carrots in the world and feed it to the bird for immediate farming use, meaning that you get a controlled crop output instantly, albeit with an okay crop. Otherwise, they're good for making those bunnyman houses which are harder to make thanks to the nerfs.
Corn: 3 Stars: Corn restores 25 hunger when eaten raw, which is pretty good by its own merit. It can also be cooked to create popcorn, which restores less hunger, but takes longer to rot. (15 days). Corn is also essential to make powdercake, an infinitely-lasting food that can be used as bait for farms or to apply spices on to be used when needed, albeit with a -3hp penalty.
Potato: 5 Stars: A cooked potato will restore 20 HP and 25 Hunger, already surpassing the other crops we talked about earlier, and if you're playing Wolfgang that hunger increases to 40. Additionally, it is used for several great crock pot recipes like Creamy Potato Puree, Spiraled Tubers, and Nightmare Pie. Did I mention that this little guy is extremely common, grows quickly, and can grow in all seasons except Summer, and requires the easiest nutrient to grow? (Manure). I find myself planting this crop very often.
Toma Root: 4 Stars: While not as potent as a potato when cooked, Toma Roots are still used in a ton of great recipes such as Vegetable Stinger, Salsa Fresca, and Warly's Moqueca. It's also a crafting recipe for Wigfrid's Rude Interlude, and can be preserved a bit longer cooked than raw. Also, it has unique nutrient requirements, making it great for pairing giant crops.
Asparagus: 3 Stars: Asparagus is the Compost crop you grow for Winter. It restores 25 hunger when cooked over a fire, comparable to the three mentioned plants above. Otherwise, it can be a substitute for the Toma Root to make Vegetable Stinger and can make Warly's Asparagazpacho for murdering idiots in winter cooling down in the Summer, though you better have a plan to preserve it because this one spoils quickly.
Eggplant: 1 Star: "Mom, can we have potato?" "No, we have potato at home." "Potato at home:"
Eggplant has the same nutrient input/output as potato and can be cooked for the same stat bonuses as a cooked potato, but it has no unique recipes outside of Hamlet besides the Stuffed Eggplant, which is a joke of a food.
Pumpkin: 3 Stars: Pumpkins restore a whopping 37.5 hunger when eaten raw or cooked, meaning it will only take you three of them to satisfy your food needs for the day. Otherwise, they can be used for pumpkin lanterns if you have fireflies lying around, pumpkin cookies if you don't want to make taffy, and a friendly scarecrow for various purposes.
Watermelon: 3 Stars: Watermelons are on carrot-tier when it comes to eating them raw or cooked for stats, but they can be used to craft Melon Hats and Melonsicles to combat the Summer heat. This is especially fantastic when you realize that Watermelons can be grown in Spring for preparation, and also Summer to make more of the aforenoted items. Honestly, I would put it at 4 stars if people didn't just dip into caves during Summer.
Dragonfruit: 5 Stars: Come on, Dragonpie alone makes this a 5-star.
Durian: 1 Star: This one might as well be a weed. It only grows during Spring, and has no unique recipes besides turning your 5-star meals into 1-star lasagna. Even for Wurt, it would be better to eat a raw pumpkin. (Durians fill her for 40 while pumpkins fill her for 50.)
Garlic: 4 Stars: Garlic can be grown in all seasons, meaning you can get a surplus of them if you get enough early. They're used in the super good Potato Puree recipe and can be used for Garlic Powder. Honestly, the 24/7 season perk is what carries this little plant.
Onion: 3 Stars: Onion is a valuable root to grow many different high-tier crockpot dishes such as Bone Bouillon, Nightmare Pie, and Moqueca. However, these can only be made by Warly, so if you don't have one on your team, you may want to resort to Salsa or Veggie Burgers. All in all, a great ingredient for Warly, but only for Warly, and its a bit hard to get early-game, and is not good to eat raw or cooked alone. It does last awhile before rotting though.
Pepper: 2 Stars: meh, it's not really good to eat raw or cooked because of the penalties, and the recipes are okay at best. It gets carried by being an extremely useful resource for Warly by turning these hot bananas into Chili Flakes.
Pomegranate: 1 Star: No unique recipes, other plants can do what it does better in terms of stats, it rots super quickly, and is resource-demanding for gardening. Hard Pass.
And that's all of them! Hopefully Klei will add more recipes for some of the unused produce like Durians and Pomegranates, but I believe that most other crops have at least one purpose, albeit some being more fringe than others.