The Revlon Skinny Liner is on the far right, and clearly boasts the slenderest brush from base to tip out of all of them.
What's more, this product also features a raven-black formula that dries quickly with a matte finish, which I definitely prefer to a shiny one. To me, a matte texture gives you more of a doe-eyed retro look as opposed to a glitzier patent-leather-like one. I also had zero problems with the color fading or imprinting into my crease throughout the day, which I've struggled with when using other liners. The only caveat is that I wish the applicator was a little firmer. It was too flexible for my taste. I find that stiffer brushes offer more control because they retain their arrow-straight edge better, but that's admittedly a personal preference.