Microman was the direct precursor to the Micronauts.
The first "Founder" Micromen were similar to Time Traveller but with bare feet and no 5mm port in back. Initially available only in kits with vehicles, this early incarnation was tied to the Henshin Cyborg line. These were released in 1974 and also included the M-115 Conning Tower, known to Micronauts fans as the Mobile Exploration Lab. The Founder Micromen came in the same four colors as Time Traveler, but unlike the MEGO figures where the chest pieces were random, these chest pieces were specific to each figure in both style and chrome color. The initial four vehicle/figure sets were Sky Rambler, Gyrotto, Hot Roader, and Beam Tripler, none of which became Micronauts. Rounding out the 1974 series were three larger vehicles known as collectively as Cosmo Cars. These were Bulk Lifter (which became the Micronauts Hydra), Space Buggy (which became Galactic Cruiser) and Sky Roader -- for which there is no Micronauts equivalent.
Pulling away from Cyborg, Microman became a full featured line all on its own in 1975. Two new sets of figures formed the core of the new lineup, with the first of the villians soon to follow. Apart from the interior mechanics (which had themselves evolved over the course of the previous year) and the continuation of chromed heads, the new figures could not have been more different from the Founders. Gone (with one exception) were the translucent bodies, gone were the delecate bare feet and the chromed chest piece. Instead, the new figures (known as the M11x and M12x series) featured shoes with 5mm holes on the bottoms and a similar hole in the figures' back as well. The Founders, which remained a part of the lineup despite being incompatible with the new look, eventually got a makeover and became the M10x series, evolving to look familiar to US fans, with shoes, 5mm ports and longer wrist cuffs. Bridging the gap between releases, Takara also produced a diecast metal version of the Founders figure. This was the beginning of the Super Steel line, which would be released overseas as Micronauts Space Glider and Galactic Warrior.
There were a great many vehicles and playsets in the 1975 lineup, most of which went on to become part of the Micronauts line. To start with, there was the Machine Car series of wind-up vehicles. These were Auto Buggy (Ultronic Scooter), Bull Crane (Crater Cruncher), Formula Z (Warp Racer) and Super Jet (Photon Sled). There were also larger, battery-powered vehicles called the Mecha Cosmo series. The first was Marine Copter, which became MEGO's Hydro Copter, and Escargo, which was slated to become Gyrotron in the US, but sadly never saw release. 1975 also begat Microman Conning Station (Astro Station), Road Station Base (Stratastation), and perhaps the most iconic Microman toy of all Robotman, which became Biotron outside Japan.
The Acroyears would also launch, along with an anti-pollution narrative. First was the A30x series, known in the US as Acroyear II, followed later by the A31x series, which MEGO decided to make into their primary Micronauts baddie, Acroyear.
While the Spy Magician figures would not see a US release, the giant Transfer Fortress would become the Micronauts' Battle Cruiser. Micro Robot would become the Micronauts' Microtron (with the same two heads but reversed standard). Drag Tiger would become the Neon Orbiter, while Marine Condor would become Aquatron.