I use very good quality silicone forms and bags and some smaller Pyrex or other oven safe dishes in mine sometimes- we are in the process of trying to lessen our environmental impact and ridding our shopping and home of unnecessary disposable items (gladwrap, single use plastic bags, plastic or paper plates etc) was the first things we did so we hardly ever use anything that’s a single use item now.
They’re generally fairly easy to clean up though so there’s really no need to use the liners that social media seems to be showing non stop.
I’m not one to buy single use disposable things like liners for the air fryer or crock pot etc. so my suggestion is to look at single person serve baking dishes and things like that instead of liners.