Rock types for certain. Seriously, very few of them are special attackers and there are no rock type special attacks (hidden power doesn't count). The majority of them are physical attackers and/or physically defensive. The few that aren't are glass cannons, or slow, or use forced to use nothing but non-rock moves. Special water and grass attacks ruin them terribly and those types are rampant in competitive, casual AND in-game. Aura sphere ruins them too and that move is somewhat common in wifi battling. Okay, they're strong as hell, and bulky too, but they're slower than a snail. Most of them, anyway. Aerodactyl was scary in gen 4 but nowadays, pfft! Flick an Ice Beam at it and watch it fall like a meteor.
But how to make a special rock-type attack that is believable?