Can you help my bland black bean burgers?

Try cumin (up to 1 tsp), cayenne (up to 1 tbsp), and/or chili powder (up to 1 tbsp). (This is how much I would use but feel free to play around it - Good luck!)

Add hot sauce

In a tiny bit of oil, fry a chopped onion over medium until it starts turning brown. Add garlic (optional), pepper, salt, if you can handle heat add a chopped cayenne or a little Cayenne powder. Add your beans and oats. egg after it cools. Finely chopped fresh cilantro. The onion and cilantro make a vast difference!

I would add 2 cloves of garlic, 1 tablespoon Worcestershire sauce, 1 tablespoon mustard, 1 tablespoon cumin seeds, 2 tablespoons ground flax, 2 tablespoons of peanut butter, 1 teaspoon soy sauce, 1 teaspoon pepper, plus about 1/3 cup of coriander leaves, and probably about half an onion, finely diced and (optional) chilli as well. (oh, I don't use egg - all those sauces help to bind everything together, but a coating in flour can help with that too). You can also experiment with adding things like BBQ sauce if u like that.

I'd add some finely diced onions first and some jarred garlic (a lot, like a whole teaspoon full of both). I put dried Thyme and a generic "Mrs. Dash" type seasoning in almost everything I cook, so add some of that, then for a black bean burger, I'd probably add a good amount (shake shake shake) premixed "Cajun" or "Caribbean jerk" McCormick spice or a touch White Pepper (yes it tastes different from black pepper, but it's potent so be careful!), some cumin (depending on how "southwestern" I wanted it to taste, as cumin is the primary flavor that's associated with tacos and chili), and if I went that route, I'd also add a big spoonful of salsa, or if I didn't want to go "southwestern" with it, maybe some Sage (sage is the primary spice in southern style breakfast sausage and thanksgiving stuffing). If you're new to herbs and spices, some basics every kitchen needs (beyond salt and black pepper) are: garlic (the stuff in a jar is far better than dried), white pepper, thyme, sage, cumin, chili powder, oregano, cajun seasoning, old bay seasoning (so good on baked or broiled fish!), rosemary, ginger powder, nutmeg, a good multi-seasoning of the Mrs. Dash variety, and of course, cinnamon. With those, you can get almost any typical American flavor. "Italian" is the oregano and thyme, "thanksgiving dinner" is the thyme, rosemary and the sage, "southwestern" is the cumin, chili, and garlic. To get "quiche" flavor you'd use garlic and nutmeg. Nutmeg is also a spice you'd associate with apple pie or pumpkin pie alongside the cinnamon but it's a surprisingly defining flavor in quiche so if you've never nailed quiche, that's the missing secret ingredient - used sparingly it's really good in savory egg dishes! White pepper goes in anything you need a bit of a depth to but don't want to be super "spicy" (it's hot in a different way, hard to explain, just try it). Cajun or Caribbean jerk go in anything you want to have some kick (they are both very bright "in your face" "hot" flavors). Don't neglect the importance of non-spice/herb seasonings too: lime juice (lime would be good in the black bean burgers too if you wanted southwestern burgers - and if you do that, make some guacamole for a topping, it's just avocado, lime, a touch of garlic and salt!), lemon juice, Worcestershire sauce, soy sauce, honey, sesame oil, and good old ketchup. Pretty much anything I make with beef has Worcestershire sauce and ketchup in it, even if it's just in the marinade. If you wanted an "asian" twist on your burgers, for example, you could use a little sesame oil, ginger, soy sauce, and garlic (and maybe a touch of honey). And after all that, I'm going to give you the "easy out": About quarter to a half of a packet of Lipton french onion soup mix (it also comes in more flavors like onion mushroom). It's a low-class but super easy solution for a lot of recipes lacking "flavor". Keep in mind it will make the sodium level skyrocket so leave out any extra salt and watch your blood pressure ;P !

1/4 c onion, 1tsp cumin, 1/2 tsp each garlic powder & onion powder, s&p. (I use real garlic though) for my fave recipe!

https://runningonrealfood.com/chickpea-veggie-burgers/
I have made those with chickpeas and the flavor was good. You could try it with black beans.

I used to make these all the time! Try chili powder, diced onions and peppers I also add corn..yummy

I made chickpea burgers not too long ago and the flavour was much improved with a little lemon juice and lemon zest. Onion. Garam Masala. Finely chopped mushrooms.