While there's still one more Decepticon to cover from the original 1984 cast of Transformers characters (and those who've been following this series can't have any mystery about who that is), my sense of balance dictates that we need to cover a couple more Autobot characters before we get to that Decepticon. Since there were only 28 characters in the 1984 group, that means picking out a couple of special "honorable mentions" to round out the "Thunderous Thirty." This is a purely arbitrary distinction based on nothing more scientific than who I, personally, think should go here. With that said, the first "honorable mention" goes to Grimlock.
Grimlock was almost certainly destined to become one of the most prominent Transformers characters before he was even released. After all, he's a Tyrannosaurus rex, most popular of all dinosaurs (at least, until Jurassic Park came along. I'd argue that Velociraptors may be more popular these days), and as I pointed out back when I did a week-long feature on the Dinobots a few years ago, kids love dinosaurs! Even scientifically-inaccurate ones! (In the 1980s only scientists knew that the upright posture seen on G1 Grimlock couldn't be accurate for the T. rex. Even museums didn't start to catch on until the early 1990s. Nowadays, most folks who follow dinosaurs know that the T. rex's body should run parallel to the ground, not perpendicular to it.)
The oddity of Grimlock's popularity is that, even back in Generation One, there were two significantly different versions of the character. I've already discussed the Marvel comics version, which featured Grimlock on two distinct occasions as the leader of the Autobots (and not just his own Dinobot sub-faction, although the less said about his first stint as leader, the better). While this version was belligerent, he wasn't exactly stupid, so much as he's a rebel who prefers actions to planning (in fact, even his crowning moment of forethought and planning, late in the comic's run, came out of his rebellious streak). Cartoon Grimlock was barely intelligent enough to rise above the purely animalistic personalities of Decepticon cassettes like Laserbeak or Ravage (again, as depicted in the cartoon). He could talk, but he was really just there to smash things. This got even worse by the time of the cartoon's third season, where Grimlock was mostly just buffoonish comic relief. His lack of intelligence was such a significant plot point that an episode was written around the fact: "Grimlock's New Brain," whereby Grimlock was temporarily endowed with super-intelligence, which enabled him to build an entirely new faction of Autobots (the Technobots) before reverting back to his moronic self.
More recent depictions of the Grimlock character have perhaps tried to blend the two versions together, with a definite edge toward the comic interpretation. I think that this is a good thing. While I might argue that Grimlock has gotten too much attention in recent years (especially as written by Simon Furman as a foil to characters like Prowl, and almost always at the other characters' expense), he really is a fun character when used properly.