The Generation 1 continuity family is the biggest, oldest, and longest-running continuity family in the Transformerscanon. Its core is all of the fiction published under the original The Transformers franchise, which got off to a bifurcated start in 1984 with the Marvel comic and Sunbow cartoon, two distinct universes starring the same cast of characters. Along with those two main continuities came many smaller continuities, mostly in the form of books.
For the next decade and a half, basically every subsequent franchise—most notably Beast Wars and Beast Machines—used bits and pieces of cartoon and comic lore as they saw fit, joining them together and extending the continuity into the distant future. It would take until 2001 for the first true "reboot" to break cleanly away from that which had gone before—and even that cartoon would eventually get subsumed back into the extremely complicated Japanese Generation 1 cartoon continuity as part of a series of complicated retcons.
In more recent years, the Generation 1 continuity family has remained a perennial favourite with modern comic publishers seeking nostalgic audiences. Companies like Dreamwave Productions, IDW Publishing, and Skybound Entertainment have published a steady stream of The Transformers-branded comics since 2003; although the majority of these stories generally take more inspiration from the more famous cartoon than the Marvel Comics continuity, both have received their fair share of sequels, spinoffs, and homages.
Within the fictional Transformers multiverse, the TransTech classify every Generation 1 continuity as a part of the "Primax" universal cluster.