Interest Stacks

The progenitor of the genre as a whole, even if some argue it doesn't count as a true mecha. I have not seen it, and doubt you will want to, but if you are curious as to the origins of mecha, it's here

If someone does not consider Testujin the first mecha, then Mazinger Z is often the show to take that place. Mazinger invented many of the key tropes of mecha as they are today, such as the robot being piloted from the inside rather than remotely, a hot-blooded MC, and various special attacks. Mazinger is also the earliest example of a super-robot anime - mecha that are action-focused and fantastical, with the mecha essentially being a superhero.

The first combination robot show and one of the key influences on later shows like Gurren Lagaan. Also notable for the much darker tone the manga would begin to take over time.

Created by the same mangaka as Mazinger, Go Nagai, Grendizer was popular overseas even if it was less successful than Mazinger in Japan, France and the Middle East especially were big Grendizer (or Goldrake in France) fans.

If Mazinger Z created super robot action, Gundam created the real robot genre with its focus on (comparatively) realistic robots, a story grounded in politics and a focus on the psychology of the main characters (particularly the main character Amuro and his rival Char). Sadly it bombed on it's first release and it would not be until the cinematic rereleases in the 1980s following Star Wars that Gundam would rise in popularity

Created by Gundam's creator, Yoshiyuki Tomino, Ideon is a step into even darker territory by the director. Notable for being an early work by him and for it's famously sad ending

Voltron is by all accounts a fairly mediocre mecha show, but is notable for - along with transformers - popularising giant robots in the anglosphere - particularly in America

Another semi-early real robot show of the 1980s, notable for kickstarting the Macross franchise and the incorporation of idol elements

One of, if not the, first isekais to reach mainstream success

An early work by Evangelion creator Hideaki Anno, and in many ways a precursor to it in terms of themes and directing style

The show that helped popularise Gundam in the English-speaking anime community

You already know what this show is

An early isekai and one of the works to help codify the genre

One of the last real robot shows to get really popular

Probably the last mecha show to be an anime-fandom-wide phenomenon rather than just appealing to mecha fans