Labyrinth 2 Aqua Forest JellyCar 2 ShapeShape Aztec Quest Fantastic Contraption Crayon Physics Deluxe
My favourite editors are the ones belonging to Labyrinth 2 and Flickitty. Labyrinth 2 because it gives you so many options and possibilities, and Flickitty because it's easy to use and it's the only game of it's type that gives you the possibility to build your very own world...
Don't forget the old classic cube runner has one online and cube runner II has a really crappy one in game.
Oh, we all seem to forget Labyrinth 1!!! It's editor is not as good as the one in Labyrinth. 2 and you won't be able to share your creations right away (you need to send them to the devs, they decide whether tp include the levels in the next update), but it's still an editor
I don't have many of these but I glanced at them in the appstore. I really like Aztec Quest's level editor because it's very clean and there are ways of using the pieces quite creatively. Simple design with lots of complexity available.