Sadly, I haven't seen most of them... yet. But here are the ones I can think of, and where/why they rate in terms of my interest, and what I can say based on reading up and watching some of the stuff from them:
- Scramble City
- Headmasters
- Masterforce
- Victory
- Zone
- Beast Wars II
- Beast Wars Neo
- Car Robots
- Micron Legend
- Super Link
- Galaxy Force
- Triple Combination: Transformers Go!
Scramble City is an OVA. Just watch it. Takes place between seasons 2 and 3 (as we know them) of the show, before the movie.
Headmasters is obvious: It's a direct continuation of the G1 series so many of us grew up with, minus/supplanting The Rebirth. People die, changes are made as a new generation takes over, and it basically acts -- to draw a comparison -- as the equivalent of "Power Rangers in Space", drawing the old era that continued on through the first several seasons to a close.
Masterforce, then, is sort of like the "Lost Galaxy" equivalent. It largely divorces itself from what came before with a new group of heroes and villains, albeit with some ties to what came before in terms of personal connections (Grand Maximus being the brother of Fortress Maximus, for example) and some returning characters. Dig deeper into the manga side, and you even get a bit with the old and new sides together. IIRC, it was originally meant to stand apart altogether, but they retconned that at some point.
Victory, as far as I know, is even more divorced. It carries along the same timeline, and there are some return appearances in new and unexpected ways, but it's mostly new villains and new heroes.
Zone is an OVA. Again, just watch it. Incidentally, it seems to feel more tied to its predecessors than Victory and maybe Masterforce.
Beast Wars II is a different, more anime take on the Beast Wars style of Transformers, with a wholly unique group of heroes and villains, though some may seem familiar due to mold and name reuse. Takes place waaaaay after most everything else, where pretty much everything we knew is long gone, and the world has moved on, bar one main element (though further ties would be established later). It reminds me of Mega Man Legends by that.
Neo is the sequel series to that, and basically ties that off.
Car Robots became Robots in Disguise here, which I saw, but is... mostly about the same? The broad strokes, at least. But instead of being reimaginings of our G1 favorites for a new millennium, it's a follow-up to Neo where the Transformers are from that II/Neo era and came back in time to the year 2000. (I'm not sure if that was a reveal in the Japanese version, so spoiled just to be safe.)
Micron Legend, Super Link, and Galaxy Force are the Japanese versions of Armada, Energon, and Cybertron, but kinda better, as far as I know? Micron got to finish production before airing, I think, and the voice recordings weren't as rushed. Saw Super Link, it's more or less the same? Galaxy Force was supposed to be its own thing there, but part of the Unicron Trilogy here, and to my understanding, they were just like "Fine..." and retconned it there as well. Main different, afaik, is that we got additional footage in the ending showing characters from the previous two shows saying good-bye. So if you saw the English ones, you probably have the gist, though they all have better, banger theme songs and closing credits in Japan. (But that's nothing new.)
Go! is basically the Headmasters of Transformers Prime, in that they ignored the last season here and instead did their own thing. Except it's more like Masterforce to some degree, because their own thing really only involved bringing back Optimus and no one else while new faces took over. And it's more anime.
Speaking personally, I'm mostly interested in the G1 continuation stuff, pretty much in descending order as it goes on, with a bump for BWII and Neo.
Hopefully, when and if I ever get around to it, I can just watch all those straight through.
