I may be misremembering, but I'm pretty sure there've been a few royal rumble matches (Or ones of similar concept and structure) off-WWE, which didn't seem to be about belt qualifiers, but were just big things that they threw because they had a bunch of big names willing to do the show but no real plotlines or matchups to work them into. Then again, I don't think I remember seeing any episodes that happened directly after those matches, so I could be wrong and their only purpose could legitimately be for special event qualifiers. I figured they'd be something that happens whenever a lot of wrestlers are disagreeing on one particular issue, and/or Managantamos has a lot of [s]extras[/s] lesser-known, Non-Filibusters that he wants to promote alongside his new, biggest show and increase his viewership.

Speaking of Non-Filibusters, I'm really wondering what FF was called before it was Filibuster now, especially considering Bustermania was already a thing, but maybe that's just the generic term. I can edit it to something different later. Bustermania itself is definitely a big tournament, sort of, with the entrants every Universal Spaceyear being determined by the amount of confirmed wins they have overall (if it is a very big federation, which Earth is not.) The best in a federation would be awarded the Federation Championship, and various Federation Champions are pitted against the champions of other galaxies in a similar manner for the Universal Championship. Assuming Earth is among the only noticably inhabitted planets in its galaxy, Alien travellers probably come to Filibuster and other remote federations all the time for an easier/shorter path to the Intergalactic Title stage when they can make the trip.