Imperial Fists

Since finishing Rogal Dorn, I've been thinking about what else to add to my Imperial Fists force. I know I want to add a Contemptor Dreadnought and another tactical squad. Beyond that, I'd love a couple of Cataphractii terminator squads with shields and chainfists and a Leviathan Dreadnought. After that I don't know though; maybe some support units like an apothecary, a centurion, or something similar.