Aight, I'm currently trying to build a map of the local multiverse during the time of LSB.

It occurs to me that I may not be aware of all the multiversal societies mentioned in common / popular fimfics - things that may be on the list.

I shall rely on (hopefully) you all to educate me!

Do you remember any multiversal societies you read about in ponyfics that would be considered a 'neighbor' to Merodi? The ETSAB and Chronomancers both count, for instance. As does the Sparkle Census.

(as does Fae Epoque, technically)

-GM, master of forums.

I am making a story that will be posted in the future that will reference the existence of the LSB.

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Nice! Have any... details I could use or things I could place on the map?

-GM, master of use.

Basically a universe sized city that float around the original Equestria, and they generally keep to thermselves unless there is a massive threat to the Equestrian part of the multiverse.

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Also if I ever decide to asscociate with your story in a deeper manner then we could do a crossovet chapter or something

Not really a society, but the plot of a fair deal stories by Estee deal with humans from multiple universes ending up in Equestria, and how the ponies deal with them and the connection to these universes.

... Following the trend of Estee's writing, the answer is 'not pleasantly'

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Mmmm, nope, don't know a multiversal society in fimfiction really, there are lots of fics that join two worlds or three at most but no central government of any kind, just alliances or collaboration of mutual benefits mostly, like in "If Whishes were ponies" or "Gentleman for Mares" or "Project Sunflower", or some conversion Beaurau like "The other side of the spectrum" where another Equestria helps earth against Evil Celestia, we have the Hasbro verse "United we Stand", mmmm, well perhaps you could use the idea of "The Lunar Guardsman" where there are portals opening at random in different worlds, and there are some organizations that use them, though the story is not advanced enough to name them or present them, just suggest there are those, anyway, that is all I have, I hope it was helpful.. or who am I kidding, none of this is what you wanted T.T.

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Sweet, once you post it, I will be checking it out :D, anything that has to do with SotS and LoS multiverse I will read.

Do the Conversion Bureau universes need to be marked? I would expect them to be pretty substantial even if they're not associated with each other.

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No, if for no other reason than because their little coalition was disbanded in chapter 100

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Spoiler for... Darn it, if I even say what stories it's a spoiler for, it will spoil things. You up for it?

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I'll take it! *feed me info.*

But tag it for the other people on this thread.

-GM, master of spoils.

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You got it, boss.

For Changeling Space Program and The Maretian by Kris Overstreet:

By the end of Maretian, Earth and Equestria have a means of transitioning between their two worlds and knowledge of many other dimensional frequencies. Also human-usable magic wands. It's unclear if they'll expand their exploration to other universes, especially after surviving an encounter with an eldritch universe only by the grace of that realm's Pinkie Pie, but the capability is there. Also, one of the Equestrian Space Program's multiversal Angel probes ended up getting destroyed and displayed on the Earth of XCOM: Ranger.

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Ah, technically already knew this from Ranger comments.

Sounds really early-level stuff, akin to Project: Sunflower's projects. Not really large enough in scope to appear on the map, but you never know.

A possible candidate for Crown Princess nabbing.

-GM, master of Crown.

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Here is the link if you wish to read the first chapter https://www.fimfiction.net/story/444862/multiversal-guardians

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Another potential thing to look into is Sunset's Isekai. It's not clear how Rarity had the connections necessary to get Sunset an entire universe-hopping bar, but there's clearly something backing her. Possibly just the Infinite Carousel, possibly something else.

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I did bring up the idea with it being part of the Infinite Carousel with Wanderer D, but he said he wanted it to be independent, so it's not gonna show up on the map.

-GM, master of smarts.

So I don't know if this is what you mean by a Multiverse organization but a group of stories some of which have been suggested are can honestly in the same area of the Multiverse they have very minor interactions though each story does generally include at least two worlds

https://www.fimfiction.net/group/207466/tatsurous-pwny-verse

Stories from this you've already put on the list include a Sparkle in his eye and three more things but I'm not sure how many others have already been suggested on the story list and later on the suggested stories forum I'll tell you which ones have already been suggested and which ones I'm going to recommend