kettles!

Heating water to boiling takes more energy than a 12V can provide. Look into portable solar setups maybe?

what kind of electric kettle devices with plugs work in your cars?

The inverter's power rating will determine what you can run. If it came stock in the vehicle the information should be in the car's manual. If it's a third-party inverter it will likely have a googleable model number.

I do have jackery's but dont want to use that power on the inside just for a kettle when i have an inverter.

? The jackery is a battery and inverter. The difference is you wouldn't have to run the car to boil water.

cooking with excess power