RIP those four generic guys in that spaceship with 80 and Yullian

They’ll show up again when they need a crowd scene in the Land of Light.

Also worth mentioning that the team ups during the battle with the Zetton army actually do have a theme.

Zero and Taiga: Both sons of legendary Ultra Brothers

Joneus and Titas: Both U40 Ultras.

Ribut and Fuma: Both themed after Asian martial arts practitioners (Ribut is a salat expert, while Fuma is a ninja)

Grigio and Yulian: Both female supporting characters who debuted as Ultras late in their respective series

80 and Mebius: The beginning and end of 25 years of peace for the Showa-verse Earth.

Melos and Z don’t team up because they have nothing in common

This is wrong, what they have in common is that they're both sexy

Couple semi-random thoughts:

Watching the Z/Tiga retrospective has really reminded me of how good those 90s shows looked. You can see the budget in a lot of those monster suits and special effects shots.

I was thinking about Absolute Conspiracy just now and how it's brought back so many different Ultras from so many obscure sources that I can't even keep track of all of them. Have we gotten Nexus, though? I can't remember if he showed up somewhere in the first section or not. Also, am I mistaken or have Leo and Astra been completely MIA here?

No Nexus, Leo, or Astra!

I'm also a little confused about Max and Mebius. Wasn't there a time when Max was based in the Showa-Verse originally, but this was quietly ret-conned and Mebius ended up being the Showa love letter? This speculation is mildly bolstered by the fact that Max's design carries obvious Showa connotations while the Mebius design is so unlike the Ultra Brothers.

No Nexus and yeah the Leo Brothers aren't in this either.

Max is as much a part of the Land of Light ultras as, say, Taiga or X. Different Earth, same homeworld.

As I remember it, Max was meant to be more of an homage to the older shows between the classic monsters, more conventional plots, and several returning actors in new roles. There are a couple episodes that are sequels to earlier shows' stories, but also some episodes that remade older stories. It's kind of occupied a weird spot in continuity where it was its own universe for awhile but it seems to have been folded into the same world with all of the other non-90s trilogy Ultras now.

Yeah, Ultraman Max is very much set in its own universe. It was deliberately a throwback to classic Showa-style Ultraman after Nexus was cancelled. Max was also the first show to bring back several iconic Showa kaiju which hadn't been seen in a long time, but outside of the aforementioned sequel episodes, it is in its own continuity. However, his guest appearance in Ultraman X established him as an Ultraman that can jump universes as well.

Spaceship crash confirmed to be more deadly than any Ultra Kaiju.