There are a number of levels to free-practice which we have in Tomiki Aikido. The first step is kakarigeiko, which is a set attack, with no resistance.. The second is hikitategeiko, which introduces light resistance (in the form of shifting stances - the top half of the body should stay relaxed) - this means you have to shift from technique to technique until you properly take uke's balance. It can be done lightly, or not. The latter requires uke's ukemi to be very good, since he never knows what technique will materialise..! After this comes randori, which is where you start introducing reversals etc...
There's a final level, which is seldom (to my understanding) practiced these days - which I don't recall the name of. It's basically 'live' fighting in the sense that the multiple ukes are trying to put you down, properly (i.e. punches, kicks etc) and so you have to make sure your responses are sharp and accurate. Obviously this is only practiced at the very highest of levels..
I don't *think* I'm missing anything out (at least in the number of types, as opposed to the descriptions).