Girlfriend's mom got us one for Xmas last year, it's a small 2.5 quart size, so we cant do large items in it but I love it and use it 2-4 times a week for side dishes.
Potatoes are awesome in it. I do wedges, hand cut fries, large diced, etc. I'll cut up 2 or 3 potatoes, toss with about a tablespoon of oil, season, and fry them at 400 for about 15-20 minutes, shaking the basket every 5 min or so. Perfect every time, nice and crispy.
Broccoli is one of my favorites. Cut into florets or decent sized mini stalks and do them like potatoes - toss in a tiny bit of oil (don't completely coat them), salt and pepper, maybe garlic powder. Fry at 400 for 5-9 minutes. Nice and crispy with a nice char, like oven roasting without the time, mess, or hot kitchen.
Almost any veggie is really good if you like roasted veggies (especially if you like a bit of char on them like we do). Carrots, cauliflower, green beans, asparagus...they're all great in the air fryer. Way better than steaming or blanching, and faster/easier than grilling or oven roasting.
I've also done boneless chicken breasts, chicken thighs, wings, frozen egg rolls, salmon...once you get the hang of it and know the right temp to fry at, it's pretty foolproof and the results are always great. I haven't made anything with it we haven't really liked.