Nervines -- herbal drugs, not superfoods, they just soothe the nervous system. Very useful, especially the few that are not also soporific. Chamomile makes most people drowsy, but lemon balm usually doesn't. You can't beat a nervine tea for relaxing after a hard day's work.
Chlorella -- actually a superfood, this algae contains many nutrients. It also makes a fantastic natural food color if you like yellow-green food. Compare with spirulina, another algae that is more blue-green. Do you like crunchy toppings? You can actually get these things in that form.
Raw cacao -- another genuine superfood, but let's be honest, most people want to cook with it. A few things, like smoothies and energy bites, are routinely made and served without heat. Add cacao nibs or powder for instant dark chocolate goodness.
Fiber -- this is a basic food component, not a superfood. The two main types are soluble (humans can digest it) and insoluble (humans can't digest it, but gut symbiotes eat it). A very useful buffer in maintaining digestive health, and something that gets stripped out of most processed foods. Look for "whole [grain]" on labels. Natural fiber is better than synthetic or ultraprocessed fiber, but it seems to be okay to mix the two for adequate consumption.
Prebiotics -- also not a superfood, overlapping with fiber, this is food for the symbiotes. Many natural sources exist, but if you have trouble getting enough, supplements are worth considering.
Digestive bitters -- not really "a" superfood, these are herbal blends that stimulate digestion, including some very old recipes. You can also just use digestive herbs to season food, which is why people put those things on heavy food to begin with. Have you seen the dish of fennel seeds at Indian restaurants? Take some, this is what they're for. Don't dick around with whatever fad Americans come up with for drinking, just look for what the Italians have been using all along. They serve little cups of this stuff before meals, so they know what they're doing with it. However, feel free to experiment with bitters as a cooking ingredient, they really punch up the flavor of things.
Extra tip: many "side effects" from antibiotics aren't actually side effects but result from the intended effect of killing microbes, as the body goes out of balance due to losing a large amount of its symbiotes. Therefore many people find that these effects can be reduced by consuming extra probiotics, prebiotics, and fiber during and after a course of antibiotics. You'll have to figure out exactly what works for you, because it's not well studied yet, but people have been quietly using this trick for decades. Just beware that "more is better" has a limit; too much will also cause unpleasant imbalances. For most people you want to raise it a notch or two above your usual level. That doesn't have to mean eating more -- you can switch from a standard yogurt with 1-2 strains to a health food yogurt with 12.