I can probably name your picky eaters favorite foods without even meeting them: crackers, chicken nuggets, bread, cheese, french fries, ice cream, pasta, yogurt...
Basically, anything white. Or beige. Or bland. You could also lump all these foods under the easiest 'textures' to chew up and manage. Perfect for the toddler who ain't got time to sit at the table and chew a piece of steak or broccoli.
As easy and convenient as most of those can be, try and limit the amount of offering you do of those. Or, if you've already got a kiddo who's stuck on those foods which offer little to no nutrients, change up what you're offering to the bland foods more nutrient dense cousin.
Instead of chicken nuggets offer grilled chicken bits. Instead of white bread, go for a multi grain. Pasta? Try veggie noodles. Kid still refusing to try the more sophisticated version of their beige foods? Make sure to offer them up with a side of 'fairytale forest trees' (broccoli) or 'pretty princess jewels' (grapes).