I got a Ninja toaster oven / air fryer for Xmas...it's amazing.
The toaster oven function is fantastic, but this is the first time I've had an air fryer.
Air Fried Chicken strips and wings; cook 10-12 minutes @ 400F, flip half way. McCormick seasonings makes some great Air Fryer Season packets; Frank's Red Hot Buffalo, Garlic Parmesan, and Loaded. I've only tried the Frank's Red Hot Buffalo, and it was excellent. I have Garlic Parmesan that I haven't tried yet.
Calzones; I just tried this last night, and they were incredible. Store bought pre-made pizza dough...I used a Kroeger brand, but Pillsbury makes some too (don't get 'thin crust', its too difficult to work with). 400F on Air Fry. Cut whatever size Calzone you want from the dough, fill with sauce, cheese, and fillings (pre-cooked). I coated the top of the raw dough with melted garlic butter. Cooked until it was golden brown (to your liking), then flipped them over and coated with more garlic butter. Maybe 7-9 minutes per side. And, of course, more pizza sauce for dipping.
You can air fry steak, hamburgers, etc...just be careful with the amount of cooking time...steak and burgers can get easily overdone if you don't watch them. I air fried a 3/4" thick flat iron @ 400F, 5 min per side, and it was overdone...like 160F internal temp. Still good, but not medium rare like I prefer.
Honestly, just Google "Easy Air Fryer Recipes" and you will find TONS of websites with a lot of amazing recipes.