Transformers 1984 Generation 1 Cartoon Series

Transformers where first seen in the "More Than Meets the Eye" pilot/mini-series.
It originated from Japan, and was animated by Japan's Animation studio and it first aired in the United States in 1984, then in the United Kingdom in early 1985.
The pilot introduced Optimus Prime's Autobots (Brawn, Bluestreak, Bumblebee, Cliffjumper, Gears, Hound, Huffer, Ironhide, Jazz, Mirage, Prowl, Ratcher, Sideswipe, Sunstreaker, Trailbreaker, Wheeljack, Windcharger, and Hauler)

While it also introduced Megatron and his Decepticons (Starscream, Skywrap, Thundercracker, Reflector, Soundwave, and Shockwave)

Many Transformers story arcs ended with the Autobots thinking they had won and in the last few seconds of the episode we would see Megatron - still alive.

The pilot was re-aired as part of the first season of the Transformers cartoon series also called "More Than Meets the Eye". But it established important new concepts that would persist through the rest of its run, such as the Decepticon Space Bridge, and debuts of new characters that would be part of the storyline also in later seasons.