As has been stated, there is a difference between a range practice session, and a pre-round/tournament warmup.
If we're talking practice session, I'm going to hit either 65 balls (medium) or 100 balls (large). I tend to structure my targets based on where the range areas are in relation to the targets (many of the ranges I practice at use grass, and therefore move their locations from day to day). I prefer to warm up with a GW or PW, swinging smoothly at a "short target" (i.e., a 100 yard shot with PW is short of my full swing). After a handful of these, I would move to hit the shot that distance would dictate (either SW, GW, or PW depending on how far the flag actually is). I probably hit 15 balls this way.
My next target is the intermediate flag (usually from 140 to 160, depending on the range and day). I hit at least 15 or 20 balls at this target, giving myself a critique for each shot (i.e., green hit, good look at birdie, short sided, etc.). I definitely spend the bulk of my range time at the short and intermediate distances.
I hit 5-10 balls at the longest iron target, using 4 iron (it's the hardest to hit consistently), and usually get a pretty good gauge of where my swing really is.
Then, Driver...I probably hit 15 to 20 with driver, until I feel my swing is "grooved", meaning I am consistently hitting the ball in a predictable pattern, trajectory and distance.
From there, typically I would hit a few hybrids, and dial back to hit "punch" shots at the intermediate flag (i.e. 6 irons at the 150 flag) to really get the feel for controlling trajectory. If I have time and enough balls I like to finish with a few half-wedges, trying to get the feel for that 50 yard mini shot. If I hit 100 balls, 50-75 are GW/PW/8 iron & Driver.