As much as this may not be exactly what the main topic of the group is (well... that actually depends on how we interpreted the term "Equestria" but it surely can refer also to the whole world shown in the MLP series) but... I started recently - again - to think more about other races (other than ponies) and their history. I mean besides ponies other races are at most just only generally depicted, usually quite vaguely... I wonder if there are some interesting stories about their history. I mean especially races, which were almost not depicted in the series.
Like gargoyles(Scorpan's race), minotaurs, centaurs, arabian horses, cows, goats, donkeys, mules, parrots(humanoid), cats(those humanoid, like Capper), storm creatures, griphons, yacks, changelings, diamond dogs or hippogriffs.

I love a lot of stories on this site. But if I had to make a list of favorite story topics, historical musings are near the top. I could link you to some of my favorites if you were interested.

7430803
You can search stories using the tags on them, such as the ‘Griffons’ tag. Looked that one up for you, there’s also a list of related tags for other races.

7430851
That would be great. I think I could find something interesting for me among them too.

7430931
Well, the point is: for many of those creatures there is no tag. There are for griffons, abyssinians (i personally don't like that name), yaks, changelings, minotaurs and hippogriffs/seaponies but that seems to be all. And not necessarily they always are historical ones (well sometimes You can't even know that if it's just something let's say about one of the young six and they actual live or is actually have some history (or at least culture) ideas for those races). Not to mention I meant mostly those undeveloped races (and from those which have tags are only minotaurs and abissynians... and only the first ones seems to have some actuall fanfiction (on abyssinians I find just one which doesn't seem to be that much historical one)) which we know hardly anything about (like for instance cenaturs and gargoyles)

7431712
One of the first that springs to mind is a two-part war epic that starts with the story called Before the Storm: The Rise of Firefly.

Then there's some of the writings of an incredibly talented writer called Cold in Gardez. I'm a fairly easy to please reader, so to me there's a lot of good and even great stories, CiG though goes beyond that.

This should get you started. Happy reading

7431712

There are for griffons, abyssinians (i personally don't like that name), yaks, changelings, minotaurs and hippogriffs/seaponies but that seems to be all.

There's also one for zebras, diamond dogs, timberwolves (!), and bat ponies, which is still a bunch of tags that you can use to do the necessary research. If you need to know more about the other minority races, then chances are, you'll find any lore pertaining to them in stories featuring one of the prominent characters--e.g. if a story has a Captain Celaeno tag, it's also really likely to contain something about those parrots.

As for filtering stories that have a lot of lore and history in them, that depends on just how well you can search. (And also on pure luck.)

7431729
Well I'm... also "fairly easy to please reader"... well partially... I mean... I tend to be demanding but usually in other areas than most people. As for Cold in Gardez work only "The Carnivore's Prayer" seems to be historically themed. And for "Before the Storm: The Rise of Firefly" gosh it is huge!
But... beside griffons it didn't seem to include any of non-pony races... (also I hope that gore tag is an overstatement, because those tag means excessive violence/blood, and excess of that never is actually good for fanfiction). So twice just the griffons, which definitely aren't one of least developed races (actually they are rather one of more developed - beside of course ponies).

7431732
Well, I didn't notice those. Well, maybe I didn't check the zebras because I already have some strong headcanon about them... but I'm not sure why i didn't think about diamond dogs... as for batponies there aren't non pony* race, and I wouldn't count timberwolves (although it is surprising) as one of intelligent species actually.
And I did tried to seek a race "by character" - to be accurate it was capper as I didn't know his race names at that moment and... well I didn't find anything historical that way. At least nothing that seemed to be so and non of checked fics was like that. As You say finding such stories (a lot of lore and history in them - and those are generally one of the best ones in my opinion) - at least in big part - on luck.
This is exactly why I ask this question here. Because perhaps somebody here read or even wrote such story.
*actually I would go rather with saying about non-pony, than "minority races", as they are minorities just in ponies country, but in matter of entire world? Many of them probably not. (For example: in my headcanon zebras are actually dominant race on other continent)

7432285
I simply mentioned these two in an off the top of my head manner. I could dig around my fimfiction libraries to see what else i could find regarding the other species.

As for the gore tag, from what I recall, Carnivore's Prayer is designed around the premise of the cost of war, so it is rather graphic, but not in a needless sense. As to the Firefly saga it is indeed long, but very much worth it.

7432285
I just remembered another set of stories that you might enjoy. It starts with a story called "Interview with a batpony", and explores a harsh world outside of Equestria's borders in exquisite detail(history, language, the works). Then there's several stories by the author Georg that touch upon ponies nocturnal brethren.

7432310

As for the gore tag, from what I recall, Carnivore's Prayer is designed around the premise of the cost of war, so it is rather graphic, but not in a needless sense.

Well that suggests that my guessing gore tag is an overstatement here is correct (actually in my opinion the essence of it is being needlessly excessive bloody/violent... well actually that means that stories that qualify to this tag in my understanding on it also disqualify a story from being suitable to be permitted... but that's another topic actually)
Also, I didn't say the Firefly saga isn't worth it. On the contrary, it seems worth it... It's just a pity it didn't seem to have more non-pony races (which I think are a highly underused theme... even though that it's somewhat understandable).
And as for "Interview with a batpony"... well actually I'm mostly interested in non-pony races, not other pony races. Actually the less the race is developed in canon the more interesting it currently is for me. And for some, there's even no proper character to seek for (like gargoyles - I don't find #scorpan tag...)

7436529
Well in Firefly there's also several chapters devoted to changelings and they are treated as a very intricate society all their own.

I'll take a look through my library and see if I can find anything that meets your criteria. I read so many stories that it's difficult to recall specifics sometimes.