So guess who forgot about this thread until just now?
1986: The results3rd Place: Ultra Magnus (16 Points)If Ultra Magnus were to be released today he would be an armored suit for Prime and he would be called ULTRA ARMOR OPTIMUS PRIME. But he was released in 1986 where you could have a white version of Prime running around in a battlesuit and pretend it was a totally different guy. And then later you could have a cartoon where Prime got turned while himself, because Sunbow are giant trolls.
2nd Place: Metroplex (18 Points)Metroplex (known in Japan as Metroflex, or more precisely as Super Happy BattleCity Metroflex, and known in the US as Metroplex) was the first Transformer who could turn into a city, complete with repair bay, helipad, garage and financial district. Also you can use the Aerialbots or Protectobots as novelty kneepads for him.
1st Place: Predaking (26 Points)For kids in the 80s Predaking was the first hint of how ludicrously huge Transformers would get, unless you were a kid in Europe where he never got released due to Hasbro's long-standing memory of the time France described America as "chunky". Predaking was composed of five guys, each of which was as big as a big guy and so his combined total size was roughly the size of a San Francisco apartment.

Pictured: roughly $1800 a month, plus utilities.
Predaking's components consisted of three predators, a prey, and whatever the hell a rhino is (does anything prey on a rhino? And if so, how? Also, why?) who were teamed up rather than eating each other. They were in bright colors and had simple features and transformations so of course everyone hates them. I kid! They each cost as much as an average mail-order bride. Then they combine into the mighty Predaking who is roughly as wide as he is tall and roughly as tall as he is awesome. In the cartoon he could demolish anyone who wasn't called Sky Lynx and in the comics he could demolish anyone except whoever had a newer toy on the shelf.
He was very heavily armed, wielding a sword that was, compared to him, roughly the size of a cheese grater; he also had a huge arm cannon and (I am not kidding here) grenade-launchers in his toes. Even though he must have spent half his time making craters and then falling into them that's still pretty damn imposing. Also he has spikey fists, because a metal fist the size of a Forever 21 isn't terrifying enough on its own.
This toy got rereleased in the 2000's, and then again in 2010 as Predabling, a version where the yellow was replaced with gold, the orange was replaced with diamonds, the red was replaced with a visually identical but more expensive shade of red and the black was replaced with black because black is always awesome.
1987 NominationsWell let's pretend this isn't going to be a one horse race. 1987 saw yet more combiner teams come out. More importantly it was the year that introduced the Headmasters (namely: Highbrow, Hardhead, Lustriouslocks, Falseteeth and Bumchin) and the Targetmasters (note: not Target exclusives). It also introduced both factions' respective hilariously oversized cityformers.
Oh, and the Throttlebots! Heh.