You won't necessarily get freakishly big just from roids. There are many different kinds with different purposes. Anything with -bol or -drol at the end of the name will be better for building sheer mass (Dianabol, Anadrol50). Winstrol and Anavar are good for getting shredded but not packing on a ridiculous amount of size. Clenbuterol (not a steroid, but has anabolic properties) is a fat burner (originally asthma medication) that helps retain mass while cutting. Then there's Human Growth Hormone, and a whole slew of other drugs. Look at baseball players that get busted, they aren't all bodybuilder jacked, but they've still taken banned substances. I'm not an expert but this is some basic stuff that I've heard and read in many different places, so there's gotta be some truth to it.
Also in regards to the programs they use...pretty much anything with basic proven exercises will work when enhanced, and it also depends on the individual. You've got some guys that say high weight low reps, some say high reps low weight, and then some that say one set per exercise to failure. Different approaches, but each one will and won't work for someone. Basically, what works for one person may not work for the next.
Of course though, it is possible naturally to get that big and ripped, it just takes a lot longer.