Going by my old Beast Wars scale, today's Leader class was indeed called Super during the Beast Wars Era. But the size class did exist in G1. The first year to have them was '85 or G1 series 2. There were 2 Super sized toys that year, Jetfire and Omega Supreme. ('86 had 5, Metroplex, Sky Lynx, Ultra Magnus Predaking and Trypticon; '87 only had Sixshot; '88 only had PM Optimus Prime; then it jumped to G2 for the first Tank Megatron and Laser Optimus Prime if you count his trailer.)

When I did my books, (Cybertronians for those who don't know) I did an Index book that showed every US toy up through RID series 2. To organize that book, I found that splitting them up into size scales was the easiest way to fit them all in with the page count I had to follow. So I came up with what I called the Beast Wars scale based off of the size classes Hasbro offered the toys in which went like this. (Micro, Mini, Basic, Deluxe, Mega, Ultra, Super, Supreme, Ultimate) Of course Beast Wars never had any Micros or Minis as it's smallest class was Basic. Since I was mixing in G1-G2 toys, I just used the old G1 names for the toys that were that scale. (Mini for Mini-Vehicles and Micro for the Micromasters.) Ultimate was added for one special toy and even to this day it is still the only toy in this class, Fortress Maximus.

Today that scale is still there we just have different names for most of them. The changes started around Armada and kept changing until it settled down with Cybertron into the the names we use now. (Mini-con, Legend, Scout, Deluxe, Voyager, Ultra, Leader, and Supreme.) The last few Supreme sized toys haven't used that name however, 25th. OP used the Masterpiece name from Japan, the large scaled Movie BB was called Ultimate, and ROTF Devastator used the name Combiner Class.

And for the record, G1 Jetfire was my first Super/Leader toy followed by Ultra Magnus and Trypticon.

 

I think it was BW season 1 Optimus Primal.

 

Actually, BW Series 1 Optimus Primal (Gorilla) and Megatron (T-Rex) were Ultra class toys, Jetbolt. The first BW Super class toy was Optimal Optimus. (it was also the first toy to use the Super class name.)

 

Well, the first Leader-sized toy I got was Armada Prime, also my first TF.  

My favorite has to be Cybertron Galvatron though.

 

TF1 Leader Megatron was mine. First Transformers toy I had bought in years!

 

I don't know if G1 Metroplex falls in this category, but he's about the same size as the Leaders.

My first one that's actually called Leader is RoTF Jetfire.

 

well jetfire was the only leader i coudl find, BUT im still hunting for prime

 

Powermaster Optimus Prime,back in 87, paid for him myself too, have no clue what happened to him...

 

My first Leader Class? Animated Megatron(Not the Shadowblade repaint).

 

My first leader figure was Transformers movie 1 Leader Megatron.